Summary: With the use of positron emission tomog raphy (PET) and the 150 steady-state- [ISF]fluorode oxyglucose combined method, the local interrelationships between the cerebral metabolic rate for oxygen (CMR02) and the cerebral metabolic rate for glucose (CMRGlc) were investigated in control subjects and in stroke pa tients. In addition to the classic in vivo autoradiographic approach, a kinetic method was used to measure CMRGlc because it was expected to be more reliable in cerebral ischemia. In control subjects local coupling be tween CBF, CMR02, and CMRGlc was confirmed, and acceptable values for the CMR02/CMRGlc ratio were found; the latter, however, was lower in white matterThe recent development of independent methods for measuring in the human brain the rates of ox ygen consumption (CMR0 2 ) and glucose utilization (CMRGlc) using positron emission tomography (PET) has revived the study of the coupling be tween CMR0 2 and CMRGlc, previously restricted to the whole brain only (Finkle stein et aI., 1981; Baron et aI., 1982; Rhodes et aI., 1982). Such in vivo studies may help us understand better the con ditions required for the occurrence and the prog nostic significance of enhanced anaerobic glycol ysis in cerebral ischemia.Address correspondence and reprint requests to Dr. Baron at Service Hospitalier Frederic Joliot, CEA Departement de Biol ogie, 91406 Orsay, France.Abbreviations used: CBV, Cerebral blood volume; CMRGlc, cerebral metabolic rate for glucose; CMR02, cerebral metabolic rate for oxygen; CT, computerized tomography; GlcAV, arterio venous glucose difference; ICA, internal carotid artery; MR, metabolic ratio; OEF, oxygen extraction fraction; OM, orbito meatal; PET, positron emission tomography.140 than in gray. Uncoupling between CMR02 and CMRGlc was observed in all stroke patients, suggesting that (1) enhanced anaerobic glycolysis occurred both in reper fused recent infarcts and in chronically ischemic tissue, and (2) substrates other than blood-borne glucose were being oxidized at the borders of recent infarcts. However, methodological uncertainties presently make such obser vations only tentative. Finally, a coupled depression of CMRO, and CMRGlc was found in the contralateral cer ebellu m . Key Words: Cerebral glucose utilization-Ce rebral oxygen consumption-Oxygen-IS -Positron emission tomography. METHODS AND PATIENTS MethodsThe steady-state oxygen-IS method of measuring CBF and CMR02 (Jones et aI., 1976) was combined with the [ISF]fluorodeoxyglucose eSFDG) technique for measuring CMRGlc (Phelps et aI., 1979; Reivich et aI., 1979). A detailed account of the combined measurement has been given earlier (Baron et aI., 1982). Briefly, consecutive continuous inhalation of trace amounts of CI502 and 1502 was performed first. Once completed, 16 min (eight pe riods) were allowed to elapse before rapid (=20 s) intra venous injection of IsFDG (3-8 mCi). Generally, three contiguous head levels, parallel to the orbitomeatal (OM) line, were studied. The coincidence photons were col lected by an EC...

Micronuclei (MN) frequencies in peripheral blood lymphocytes have been used worldwide as a biomarker of chromosomal damage for genotoxicity testing and biomonitoring studies. Automation of MN analysis would provide faster and more reliable results with minimizing subjective MN identification. We developed an automated facility for the scoring of the in vitro MN cytokinesis-block assay for biomonitoring on Giemsa-stained slides, fulfilling the following criteria: applicable to the cytokinesis-block micronucleus methodology, discriminating between mono-, bi- and polynucleated cells, MN scoring according to HUMN scoring criteria, false-negative MN rate <10% and false-positive (FP) MN rate <1%. We first adapted the slide preparation protocol to obtain an optimal cell density and dispersion, which is important for image analysis. We developed specific algorithms starting from the cell as a detection unit. The whole detection and scoring process was separated into two distinct steps: in the first step, the cells and nuclei are detected; then, in the second step, the MN are searched for in the detected cells. Since the rate of FP MN obtained by the automatic analysis was in the range of 0.5-1.5%, an interactive visual validation step was introduced, which is not time consuming and allows quality control. Validation of the automated scoring procedure was undertaken by comparing the results of visual and automated scoring of micronucleated mono- and binucleated cells in human lymphocytes induced by two clastogens (ionizing radiation and methyl methane-sulphonate), two aneugens (nocodazole and carbendazim) and one apoptogen (staurosporine). Although the absolute MN frequencies obtained with automated scoring were lower as compared to those detected by visual scoring, a clear dose response for MNBN frequencies was observed with the automated scoring system, indicating that it is able to produce biologically relevant and reliable results. These observations, together with its ability to detect cells, nuclei and MN in accordance with the HUMN scoring criteria, confirm the usability of the automated MN analysis system for biomonitoring.

No abstract

As part of a project to develop high throughput versions of the comet assay (single cell gel electrophoresis), with a consequent need for more efficient scoring, we have compared the performance of visual scoring, automated and semi-automated image analysis when assessing comets in the same set of gels from dose-response experiments with typical DNA-damaging agents. Human lymphoblastoid TK-6 cells were treated with concentrations of methylmethanesulphonate between 0.04 and 0.6 mM, and peripheral human lymphocytes were incubated, after embedding in agarose, with H(2)O(2) concentrations from 2.5 to 160 μM. All three scoring methods proved capable of detecting a significant level of damage at the lowest concentration of each agent. Visual scoring systematically overestimates low levels of damage compared with computerised image analysis; on the other hand, heavily damaged comets are less efficiently detected with image analysis. Overall, the degree of agreement between the scoring methods is within acceptable limits according to a Bland-Altman analysis.

Brain protein synthesis may be evaluated in vivo by a PET three compartment methionine model. 14 human brain tumor patients were studied. Protein synthesis rate (PSR) was increased in any glial tumor even in low grades, but this increase was statistically more important in anaplastic tumor. Radiotherapy action was evaluated in two patients. Local tumoral PSR was reduced to normal brain PSR after treatment. No difference was seen in normal cortex contralateral to the lesion between pre and post radiotherapy examination. 11 C-L-Methionine incorporation measured by PET looks as a very sensitive method for studying tumor metabolism and treatment effects.