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Biomedical subjects

V Maunoury

Publications and source records attributed to V Maunoury.

At least 37 records · Page 2Linked to original sources
PubMed1994

In vivo pH measurement and imaging of tumor tissue using a pH-sensitive fluorescent probe (5,6-carboxyfluorescein): instrumental and experimental studies.

This study evaluated the effectiveness of dual-wavelength ratio fluorescence imaging using a pH-dependent indicator (5,6-carboxyfluorescein, 5,6-CF) for in vivo pH mapping of tissue. A prototype version of a highly sensitive fluorescence imaging device consisting of a modified xenon lamp, an image-intensified camera and a digital image-processing system has been developed. 5,6-Carboxyfluorescein was used because its fluorescence emission increases as a function of pH in the physiological (6.0-7.4) pH range. The ratio of fluorescence intensities obtained with the imaging system has been calibrated using aqueous 5,6-CF standards at various pH values. Because the pH of interstitial fluid of malignant tumors tends to be lower than that of normal tissue and can be depressed by glucose administration, experiments were performed on 10 CDF mice bearing lymphoid leukemia P388 grafted subcutaneously. The range of linearity of the calibration curve was obtained between 5.3 and 6.7 with a measured pKa value of 5.93. Consequently the maximum sensitivity was observed in this range. The calculated pH from ratio images was 6.21 +/- 0.12 in tumorous tissue. This value was equivalent to those obtained at the same time using microelectrodes (6.2 +/- 0.3). These experiments showed that a dose of 5 mg/kg 5,6-CF and an excitation power density of 2.5 mW/cm2 are sufficient to give a fluorescent pH image of tumors. The limitation of 5,6-CF for the in vivo mapping of tissue results from its low pKa and consequent range of sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[Pancreatic-portal fistula. A rare complication of chronic pancreatitis].

We report a 40-year-old patient with complication of chronic pancreatitis as a pancreatico-portal fistula. The patient had subcutaneous nodular fat necrosis of the lower limbs resembling Weber-Christian syndrome, and amylasic ascitis. The diagnosis was established with retrograde endoscopic cholangio-pancreatography which found three pancreatic pseudocysts and a communication with the portal venous system. A portal thrombosis with cavernum was studied with color echo-Doppler and arteriography. The echo-endoscopy was performed for the first time in this complication and its significance estimated. The evolution was quickly and spontaneously favourable. That is a very rare complication of chronic pancreatitis and an expectant conservative management can be adopted.

Adult↗
PubMed1994

[Absence of subrenal inferior vena cava revealed by rupture of duodenal varices in an adult].

This report concerns a case of absence of caudal inferior vena cava revealed by gastrointestinal bleeding from isolated duodenal varices by an adult. The diagnosis of duodenal varices was performed by ultrasonographic endoscopy. Development of duodenal varices in absence of portal hypertension is uncommon. Involvement of cavo-portal collateral circulation in case of inferior vena cava obstruction is unusual and duodenal varices are still more rarely encountered. Diagnosis was ultimately supported by femoral venous angiography showing the absence of inferior vena cava and a venous return from the right lumbar vein into the portal vein via the duodenal varices. The absence of caudal portion of inferior vena cava is more probably related to neo-natal thrombosis than to a true atresia.

Adult↗
PubMed1993

[Hepatic calcifications revealing epithelioid hemangioendothelioma].

This report concerns a case of hepatic epithelioid hemangioendothelioma presenting with liver enlargement, multiple hepatic calcifications on the plain abdominal film and bilateral interstitial pneumonia. Epithelioid hemangioendothelioma is an unusual soft tissue tumor of "intermediate malignancy" characterized by a multicentric involvement of the liver and originating from endothelial cells. Histopathologic diagnosis may be difficult because of possible confusion with sclerosing epithelial tumors.

Adult↗
PubMed1992

Characterization of tumorous and normal tissue using a pH-sensitive fluorescence indicator (5,6-carboxyfluorescein) in vivo.

The pH of the interstitial fluid of malignant tumours tends to be lower than that of normal tissue and is depressed by glucose administration. This study aimed to evaluate the effectiveness of dual-wavelength fluorometry using a pH-dependent indicator (5,6-carboxyfluorescein: 5,6-CF) for the detection of tumour areas in vivo. 5,6-CF has two main characteristics: it has two wavelengths of maximum absorbance (465 and 490 nm) and its fluorescence emission (maximum, 515 nm) increases as a function of pH in the physiological pH range of 6-7.4. The experimental study was performed on 28 CDF mice bearing lymphoid leukaemia P388 grafted subcutaneously. The tissue pH values were evaluated from the ratio of the fluorescence intensities (I490/I465) on the basis of a calibration curve linking pH measurements performed within the tissue using a microelectrode and values of the fluorescence intensity ratio. The fluorescence intensity reached its maximum value 60 min after 5,6-CF and glucose administration, followed by a plateau (90 min) when the ratios remained constant at 1.79 +/- 0.05 for normal tissue and 1.35 +/- 0.04 for tumour tissue (p less than 0.005). These results were correlated with the pH measurements in accordance with the calibration curve. This study validates the relevance of dual-wavelength fluorometry using a pH-dependent indicator to characterize in vivo normal and tumour tissues after glucose administration.

Animals↗