Characterisation of tumour blood flow using a 'tissue-isolated' preparation.

Tumour blood flow was characterised in a 'tissue-isolated' rat tumour model, in which the vascular supply is derived from a single artery and vein. Tumours were perfused in situ and blood flow was calculated from simultaneous measurement of (1) venous outflow from the tumour and (2) uptake into the tumour of radiolabelled iodo-antipyrine (IAP). Comparison of results from the two measurements enabled assessment of the amount of blood 'shunted' through the tumours with minimal exchange between blood and tissue. Kinetics of IAP uptake were also used to determine the apparent volume of distribution (VDapp) for the tracer and the equilibrium tissue-blood partition coefficient (lambda). lambda was also measured by in vitro techniques and checks were made for binding and metabolism of IAP using high-pressure liquid chromatography. VDapp and lambda were used to calculate the perfused fraction (alpha) of the tumours. Tumour blood flow, as measured by IAP (TBFIAP), was 94.8 +/- 4.4% of the blood flow as measured by venous outflow, indicating only a small amount of non-exchanging flow. This level of shunting is lower than some previous estimates in which the percentage tumour entrapment of microspheres was used. The unperfused fraction ranged from 0 to 20% of the tumour volume in the majority of tumours. This could be due to tumour necrosis and/or acutely ischaemic tumour regions. For practical purposes, measurement of the total venous outflow of tumours is a reasonable measure of exchangeable tumour blood flow in this system and allows for on-line measurements. Tracer methods can be used to obtain additional information on the distribution of blood flow within tumours

Resistance to flow through tissue-isolated transplanted rat tumours located in two different sites

The perfusion characteristics of the P22 carcinosarcoma were investigated in tissue-isolated tumour preparations in the ovarian and inguinal fat pads of BD9 rats. Tumours were perfused with a physiological buffer of known viscosity and changes in perfusion pressure were recorded at different perfusion rates in an ex vivo system. At perfusion pressures exceeding 30-40 mmHg tumour flow rate was directly proportional to the perfusion pressure in all tumours, indicating a constant resistance to flow. An apparent positive pressure difference across the tumour vasculature of 20-30 mmHg occurred under conditions of zero flow in either site. At low perfusion pressures, the flow resistance increased sharply due to increases in the geometric resistance of the tumours. These findings are in accord with previously published data. Geometric resistance increased with tumour volume in both sites and was approximately five times greater in the inguinal tumours than it was in the ovarian tumours, on a weight to weight basis. The dependence of tumour geometric resistance on perfusion pressure differs from the situation in normal tissues and may provide a means of manipulating the tumour microcirculation to the exclusion of the systemic blood supply. The dependence of geometric resistance on tumour site may partly explain why tumours located in different sites respond differently to various forms of therapy

The endothelin B (ETB) receptor agonist IRL 1620 is highly vasoconstrictive in two syngeneic rat tumour lines: potential for selective tumour blood flow modification

The vascular effects of the endothelin B (ETB) receptor agonist IRL 1620 were investigated in the rat P22 carcinosarcoma and a range of normal tissues in BDIX rats. Tissue blood flow rate was calculated from measurements of tissue uptake of radiolabelled iodoantipyrine. A comparison of vascular effects in the P22 tumour and the HSN sarcoma growing in CBH/CBi rats was made using laser Doppler flowmetry, showing similar effects of IRL 1620, with red cell flux rapidly decreasing by 50–60% and then returning to control levels within approximately 30 min. This corresponded to similar levels but different spatial organisation of ETB binding sites in the two tumours, as measured by autoradiography. The decrease in tumour blood flow and an increase in vascular resistance suggest that the vascular component of ETB receptors in the P22 tumour is localised on contractile elements rather than on endothelial cells. ETA receptors were also identified. Vasoconstriction occurred uniformly throughout the P22 tumour mass, consistent with a measured homogeneous distribution of ETB receptors. IRL 1620 caused vasoconstriction in normal skeletal muscle, kidney and small intestine of the BDIX rat as well as in tumour, but did not affect blood flow in other tissues. These effects could be useful for limiting toxicity of certain chemotherapeutic agents. Fully functional ETB receptors are clearly expressed on tumour vasculature and IRL 1620 shows promise for short-term modification of tumour blood flow. Expression levels of ETB receptors on the tumour vasculature could be useful for predicting which tumours are likely to respond to IRL 1620

Reduced capacity of tumour blood vessels to produce endothelium-derived relaxing factor: significance for blood flow modification.

The effect of nitric oxide-dependent vasodilators on vascular resistance of tumours and normal tissue was determined with the aim of modifying tumour blood flow for therapeutic benefit. Isolated preparations of the rat P22 tumour and normal rat hindlimb were perfused ex vivo. The effects on tissue vascular resistance of administration of sodium nitroprusside (SNP) and the diazeniumdiolate (or NONO-ate) NOC-7, vasodilators which act via direct release of nitric oxide (NO), were compared with the effects of acetylcholine (ACh), a vasodilator which acts primarily via receptor stimulation of endothelial cells to release NO in the form of endothelium-derived relaxing factor (EDRF). SNP and NOC-7 effectively dilated tumour blood vessels after preconstriction with phenylephrine (PE) or potassium chloride (KCl) as indicated by a decrease in vascular resistance. SNP also effectively dilated normal rat hindlimb vessels after PE/KCl constriction. Vasodilatation in the tumour preparations was accompanied by a significant rise in nitrite levels measured in the tumour effluent. ACh induced a significant vasodilation in the normal hindlimb but an anomalous vasoconstriction in the tumour. This result suggests that tumours, unlike normal tissues are incapable of releasing NO (EDRF) in response to ACh. Capacity for EDRF production may represent a difference between tumour and normal tissue blood vessels, which could be exploited for selective pharmacological manipulation of tumour blood flow

Visual outcomes and predictors in optic pathway glioma: a single centre study

BACKGROUND/AIMS: Optic pathway gliomas (OPGs) may cause progressive visual loss despite chemotherapy. Newer, less toxic treatments might be given earlier, depending on visual prognosis. We aimed to investigate the prognostic value of visual evoked potentials (VEP) and optical coherence tomography (OCT). METHODS: A retrospective study of OPG patients (treated 2003–2017) was conducted. Primary outcome was PEDIG category visual acuity in better and worse eyes (good  = 0.7 logMAR). Binary logistic regression analysis was used to identify predictors of these outcomes. RESULTS: 60 patients (32 Neurofibromatosis type 1 [NF1] and 28 sporadic) had median presentation age 49 months (range 17–183) (NF1) and 27 months (range 4–92) (sporadic). Median follow up was 82 months (range 12–189 months). At follow up 24/32 (75%) of NF1 children and 14/28 (50%) of sporadic children had good better eye visual acuity and 11/32 (34%) of NF1 children and 15/28 (54%) of sporadics had poor worse eye acuity. Mean peripapillary retinal nerve fibre layer (RNFL) thickness predicted good better eye final acuity (OR 0.799, 95%CI 0.646–0.987, p = 0.038). Presenting with visual symptoms (OR 0.22 95% CI 0.001–0.508, p = 0.017) and poorer VEP scores (OR 2.35 95% CI 1.1–5.03, p = 0.027) predicted poor worse eye final acuity. 16 children had homonymous hemianopias at follow up, predicted by poor presenting binocular VEP score (OR 1.449 95%CI 1.052–1.995, p = 0.02). CONCLUSIONS: We found that both RNFL thickness on OCT and VEP were useful in predicting future visual acuity and vision and potentially in planning treatment. We had a high prevalence of homonymous hemianopia

Comparison of RBE values of high- LET α-particles for the induction of DNA-DSBs, chromosome aberrations and cell reproductive death

<p>Abstract</p> <p>Background</p> <p>Various types of radiation effects in mammalian cells have been studied with the aim to predict the radiosensitivity of tumours and normal tissues, e.g. DNA double strand breaks (DSB), chromosome aberrations and cell reproductive inactivation. However, variation in correlations with clinical results has reduced general application. An additional type of information is required for the increasing application of high-LET radiation in cancer therapy: the Relative Biological Effectiveness (RBE) for effects in tumours and normal tissues. Relevant information on RBE values might be derived from studies on cells in culture.</p> <p>Methods</p> <p>To evaluate relationships between DNA-DSB, chromosome aberrations and the clinically most relevant effect of cell reproductive death, for ionizing radiations of different LET, dose-effect relationships were determined for the induction of these effects in cultured SW-1573 cells irradiated with gamma-rays from a Cs-137 source or with α-particles from an Am-241 source. RBE values were derived for these effects. Ionizing radiation induced foci (IRIF) of DNA repair related proteins, indicative of DSB, were assessed by counting gamma-H2AX foci. Chromosome aberration frequencies were determined by scoring fragments and translocations using premature chromosome condensation. Cell survival was measured by colony formation assay. Analysis of dose-effect relations was based on the linear-quadratic model.</p> <p>Results</p> <p>Our results show that, although both investigated radiation types induce similar numbers of IRIF per absorbed dose, only a small fraction of the DSB induced by the low-LET gamma-rays result in chromosome rearrangements and cell reproductive death, while this fraction is considerably enhanced for the high-LET alpha-radiation. Calculated RBE values derived for the linear components of dose-effect relations for gamma-H2AX foci, cell reproductive death, chromosome fragments and colour junctions are 1.0 ± 0.3, 14.7 ± 5.1, 15.3 ± 5.9 and 13.3 ± 6.0 respectively.</p> <p>Conclusions</p> <p>These results indicate that RBE values for IRIF (DNA-DSB) induction provide little valid information on other biologically-relevant end points in cells exposed to high-LET radiations. Furthermore, the RBE values for the induction of the two types of chromosome aberrations are similar to those established for cell reproductive death. This suggests that assays of these aberrations might yield relevant information on the biological effectiveness in high-LET radiotherapy.</p

Anti-cancer effects and mechanism of actions of aspirin analogues in the treatment of glioma cancer

INTRODUCTION: In the past 25 years only modest advancements in glioma treatment have been made, with patient prognosis and median survival time following diagnosis only increasing from 3 to 7 months. A substantial body of clinical and preclinical evidence has suggested a role for aspirin in the treatment of cancer with multiple mechanisms of action proposed including COX 2 inhibition, down regulation of EGFR expression, and NF-κB signaling affecting Bcl-2 expression. However, with serious side effects such as stroke and gastrointestinal bleeding, aspirin analogues with improved potency and side effect profiles are being developed. METHOD: Effects on cell viability following 24 hr incubation of four aspirin derivatives (PN508, 517, 526 and 529) were compared to cisplatin, aspirin and di-aspirin in four glioma cell lines (U87 MG, SVG P12, GOS – 3, and 1321N1), using the PrestoBlue assay, establishing IC50 and examining the time course of drug effects. RESULTS: All compounds were found to decrease cell viability in a concentration and time dependant manner. Significantly, the analogue PN517 (IC50 2mM) showed approximately a twofold increase in potency when compared to aspirin (3.7mM) and cisplatin (4.3mM) in U87 cells, with similar increased potency in SVG P12 cells. Other analogues demonstrated similar potency to aspirin and cisplatin. CONCLUSION: These results support the further development and characterization of novel NSAID derivatives for the treatment of glioma

A multicenter phase II study of induction chemotherapy with FOLFOX-4 and cetuximab followed by radiation and cetuximab in locally advanced oesophageal cancer

"Background: Preoperative chemoradiotherapy (CRT) improves the survival of patients with oesophageal cancer when compared with surgery alone.. . Methods: We conducted a phase II, multicenter trial of FOLFOX-4 and cetuximab in patients with locally advanced oesophageal cancer (LAEC) followed by daily radiotherapy (180 cGy fractions to 5040 cGy) with concurrent weekly cetuximab. Cytokines levels potentially related to cetuximab efficacy were assessed using multiplex-bead assays and enzyme-linked immunosorbent assay at baseline, at week 8 and at week 17. Primary end point was complete pathological response rate (pCR).. . Results: In all, 41 patients were enroled. Among 30 patients who underwent surgery, a pCR was observed in 8 patients corresponding to a rate of 27%. The most frequent grade 3\/4 toxicity was skin (30%) and neutropenia (30%). The 36-month survival rates were 85 and 52% in patients with pathological CR or PR vs 38 and 33% in patients with SD or PD.. . Conclusions: Incorporating cetuximab into a preoperative regimen for LAEC is feasible; no correlation between cytokines changes and patient outcome was observed. Positron emission tomography\/computed tomography study even if influenced by the small number of patients appears to be able to predict patients outcome both as early and late metabolic response.. . "Background: Preoperative chemoradiotherapy (CRT) improves the survival of patients with oesophageal cancer when compared with surgery alone. Methods: We conducted a phase II, multicenter trial of FOLFOX-4 and cetuximab in patients with locally advanced oesophageal cancer (LAEC) followed by daily radiotherapy (180 cGy fractions to 5040 cGy) with concurrent weekly cetuximab. Cytokines levels potentially related to cetuximab efficacy were assessed using multiplex-bead assays and enzyme-linked immunosorbent assay at baseline, at week 8 and at week 17. Primary end point was complete pathological response rate (pCR). Results: In all, 41 patients were enroled. Among 30 patients who underwent surgery, a pCR was observed in 8 patients corresponding to a rate of 27%. The most frequent grade 3/4 toxicity was skin (30%) and neutropenia (30%). The 36-month survival rates were 85 and 52% in patients with pathological CR or PR vs 38 and 33% in patients with SD or PD. Conclusions: Incorporating cetuximab into a preoperative regimen for LAEC is feasible; no correlation between cytokines changes and patient outcome was observed. Positron emission tomography/computed tomography study even if influenced by the small number of patients appears to be able to predict patients outcome both as early and late metabolic response. © 2011 Cancer Research UK All rights reserved

Dose-Dependent Onset of Regenerative Program in Neutron Irradiated Mouse Skin

Background: Tissue response to irradiation is not easily recapitulated by cell culture studies. The objective of this investigation was to characterize, the transcriptional response and the onset of regenerative processes in mouse skin irradiated with different doses of fast neutrons. Methodology/Principal Findings: To monitor general response to irradiation and individual animal to animal variation, we performed gene and protein expression analysis with both pooled and individual mouse samples. A high-throughput gene expression analysis, by DNA oligonucleotide microarray was done with three months old C57Bl/6 mice irradiated with 0.2 and 1 Gy of mono-energetic 14 MeV neutron compared to sham irradiated controls. The results on 440 irradiation modulated genes, partially validated by quantitative real time RT-PCR, showed a dose-dependent up-regulation of a subclass of keratin and keratin associated proteins, and members of the S100 family of Ca2+-binding proteins. Immunohistochemistry confirmed mRNA expression data enabled mapping of protein expression. Interestingly, proteins up-regulated in thickening epidermis: keratin 6 and S100A8 showed the most significant up-regulation and the least mouse-to-mouse variation following 0.2 Gy irradiation, in a concerted effort toward skin tissue regeneration. Conversely, mice irradiated at 1 Gy showed most evidence of apoptosis (Caspase-3 and TUNEL staining) and most 8-oxo-G accumulation at 24 h post-irradiation. Moreover, no cell proliferation accompanied 1 Gy exposure as shown by Ki67 immunohistochemistry. Conclusions/Significance: The dose-dependent differential gene expression at the tissue level following in vivo exposure to neutron radiation is reminiscent of the onset of re-epithelialization and wound healing and depends on the proportion of cells carrying multiple chromosomal lesions in the entire tissue. Thus, this study presents in vivo evidence of a skin regenerative program exerted independently from DNA repair-associated pathways