Search results for " blood flow"

Vascularity, perfusion rate and local tissue oxygenation of tumors derived from ras-transformed fibroblasts.

2007

Tumors derived from ras-transformed rat fibroblasts were investigated in order to gain insight into possible interrelationships between oncogenic transformations and therapeutically relevant parameters of the metabolic micromilieu of solid tumors in vivo. Tumors grew in nude mice after injection of in vitro-passaged cells. Growth rates, early stages of angiogenesis, perfusion and tissue oxygenation were assessed. Compared with the parental cell line, both ras transformants grew very rapidly and exhibited an early onset of angiogenesis. Perfusion rates of one ras-transformed tumor line were similar to those of the parental tumors whereas reduced flow values were detected in tumors of the oth…

Pixel-to-pixel correlation between images of absolute ATP concentrations and blood flow in tumours

1992

Iodo(14C-)antipyrine autoradiography and imaging bioluminescence have been combined to obtain pixel-to-pixel correlations between absolute values for local blood flow and ATP concentrations at a microscopical level within designated areas in hamster melanomas. Positive pixel-to-pixel correlations were obtained in 4 of 6 tumours. Both flow and ATP values were less in mostly necrotic than in mostly viable tumour regions. The data provide evidence for the energetic state of cancer cells being strongly influenced by the efficiency of tumour microcirculation in several but not in all malignancies investigated. Images Figure 1

Abstract 4258: Preliminarily results of the Oncohabitats Study: A multicentre validation of overall survival (OS) estimation of patients with gliobla…

2019

Abstract We report preliminarily results of an international retrospective study (NCT03439332) analyzing the prognostic value of the early assessment of vascular architecture of glioblastoma (GBM). The initial cohort included 300 pts treated at 7 European hospitals. Multiparametric images were processed by Oncohabitats (www.oncohabitats.upv.es) to obtain the cerebral blood volume (CBV) and cerebral blood flow (CBF) from 4 automatically delimited regions of interest (ROIs): high angiogenic tumor (HAT), low angiogenic tumor (LAT), infiltrating peripherial edema (IPE), and vasogenic peripherial edema (VPE). Uniparametric Cox regression models and Kaplan-Meier analysis were developed to test pr…

Blood flow and metabolic microenvironment of brain tumors

1994

Summarizing thesein vivo data in the context of brain tumor therapy, the following aspects are of particular importance: Low and heterogeneous tumor blood flow may — in addition to the limiting effects of the blood-brain barrier — result in compromised delivery of drugs from blood to the tissue. Low tumor pO2 reduces sensitivity to standard radiation and ‘O2-dependent’ anticancer drugs. Treatment efficacy may be further altered by changes of tumor pH. Particularly acidosis can decrease radiation sensitivity and modulate the cytotoxicity of anticancer drugs. In the following presentations, these aspects will be discussed regardingin vivo data obtained with positron emission tomography.

Arterial pCO2 and Blood Flow in Different Parts of the Central Nervous System of the Anesthetized Cat

1969

It cannot be regarded as proven that the mechanisms involved in the regulation of local circulation are identical in all parts of the central nervous system. Evidence has been presented that carbon dioxide exerts differential effects in different parts of the CNS [2, 3, 7, 10].

Delayed filling of retinal and ciliary circulation after central retinal artery occlusion

1988

The filling times of the retinal and choroidal circulation were evaluated in 17 patients with central retinal artery occlusion by means of fluorescein angiography. A correlation between the filling times of the two circulations was found. However, two filling patterns were seen: first, both fillings delayed; second, both fillings normal. It is probable that in the former case an obstructive disease of the carotid arteries exists, while in the latter case an important pathology of the carotid arteries is lacking, favouring a rapid restoration of the retinal circulation. This hypothesis seems to be confirmed by the results of the Doppler velocimetry of the carotid arteries.

Characterization of the cortical laser-doppler flow and hippocampal degenerative patterns after global cerebral ischaemia in the goat.

1998

Large-animal models offer several advantages in the study of cerebral ischaemia: easier control of physiological variables, easier neuropathological evaluation, etc. In the present study we have taken advantage of the unique cerebrovascular anatomy of the goat to reproduce a model of reversible, incomplete, global cerebral ischaemia in a large-sized animal species, in which the effects of successive manoeuvres to stop and re-start cerebral blood flow can be recorded continuously. Early cortical laser-Doppler flow response (up to 2 h) and delayed neuronal degeneration (7 days) in the hippocampal CA1 subfield have been analysed in goats undergoing 5, 10 or 20 min of transient, global cerebral…

Regional Cerebral Blood Flow in Cases of Brain Tumor

1969

The present series consists of 21 patients with brain tumors: 12 malignant gliomas, 4 oligo- dendro gliomas, 3 meningeomas and 2 metastases, studied by the133Xe-gamma-clearance rCBF method. In 16 patients at least 3 determinations of rCBF were performed: a) in the resting state, R; b) during hyperventilation, HV, and c) during hypertension, HT. Of the remaining 5 patients, 1 was studied only during R, while the other 4 were submitted either to HV or to HT additionally to the R study. The average age of this series of patients was 47 years, the youngest being 19 and the oldest 64. rCBF studies had to be performed under general anesthesia (N2O + O2, Engstrom respirator) in 5 instances in whic…

Destruction of Kupffer’s cells increases total liver blood flow and decreases ischemia reperfusion injury in pigs

2000

Neuronal Activity Drives Localized Blood-Brain-Barrier Transport of Serum Insulin-like Growth Factor-I into the CNS

2010

Upon entry into the central nervous system (CNS), serum insulin-like growth factor-1 (IGF-I) modulates neuronal growth, survival, and excitability. Yet mechanisms that trigger IGF-I entry across the blood-brain barrier remain unclear. We show that neuronal activity elicited by electrical, sensory, or behavioral stimulation increases IGF-I input in activated regions. Entrance of serum IGF-I is triggered by diffusible messengers (i.e., ATP, arachidonic acid derivatives) released during neurovascular coupling. These messengers stimulate matrix metalloproteinase-9, leading to cleavage of the IGF binding protein-3 (IGFBP-3). Cleavage of IGFBP-3 allows the passage of serum IGF-I into the CNS thro…