Direct evidence that natural killer cells in nonimmune spleen cell populations prevent tumor growth in vivo.

Relatively large numbers of nonimmune spleen cells do not protect against the local growth of two lymphomas. However, this heterogeneous population of splenic lymphocytes contains a subset of cells that efficiently protects against in vivo tumor growth. This cell population (cell-surface phenotype Thyl.2(-)Ig(-)Ly5.1(+)) represents less than 5 percent of the spleen cell population and is responsible for in vitro NK-mediated lysis. Although these studies clearly and directly demonstrate that Ly5(+) NK cells selected from a heterogeneous lymphoid population from nonimmune mice can protect syngeneic mice against local in vivo growth of two different types of tumor cells (in contrast to other lymphocyte sets within the spleen), they do not directly bear upon the role of NK cells in immunosurveillance. They do indicate that highly enriched Ig(-)Thyl(-)Ly5(+) cells, which account for virtually all in vitro NK activity, can retard tumor growth in vivo. It is difficult to ascribe all anti-tumor surveillance activity to NK cells, because they probably do not recirculate freely throughout the various organ systems of the body. Perhaps NK ceils may play a role in prevention of neoplastic growth within discrete anatomic compartments where there is rapid differentiation of stem cells to mature progeny (e.g., bone marrow, spleen, and portions of the gastrointestinal tract)and may normally act to regulate the growth and differentiation of non-neoplastic stem cells. Long-term observation of chimeric mice repopulated with bone marrow from congenic or mutant donors expressing very low or very high NK activity may help to answer these questions.

Analysis of absorption spectra changes induced by temperature lowering on phycobilisomes, thylakoids and chlorophyll-protein complexes.

Using fourth derivative analysis, differences between room and low temperature absorption spectra were studied. The positions of most absorption bands of the water-soluble, accessory pigment complex, the phycobilisome, remained unchanged after cooling. The stability of the wavelength positions of chlorophyll a forms in vivo as a function of temperature (Gulyaev, B.A. and Litvin, F.F. (1967) Biofizika 12, 845--854) was generally confirmed. The wavelength positions of all chlorophyll a forms in the P-700 chlorophyll a protein complex were unchanged when the preparations were cooled to -196 degrees C. Likewise, with other chlorophyll-containing materials: the light-harvesting chlorophyll a/b protein complex and the thylakoids of higher plants, algae, and cyanobacteria, the wavelengths positions of most chlorophyll a forms were stable upon cooling. An exception was a 680 nm chlorophyll a band which was generally split at low temperature into two bands with the materials investigated. An interpretation of the multiplicity of chlorophyll spectral forms and the spectral changes induced by cooling for these forms is given using exciton theory and the energy-coupling variation of chlorophyll a molecules.

Soil characteristics, heavy metal availability and vegetation recovery at a former metallurgical landfill: Implications in risk assessment and site restoration.

Pedological and botanical characteristics of a former metallurgical landfill were examined to assess the risks of heavy metals mobility and to evaluate remediation feasibility. In addition to very high heavy metals levels (Cu, Cr, Mn, Ni, Pb, Zn), the soil was characterized by a lack of clear horizonation, a relatively high pH, a high mineral and organic carbon contents, a low nitrogen level and a high C/N ratio. A two step sequential extraction showed that heavy metals were poorly labile (i.e. not soluble in diluted CaCl2), indicating that their leaching under natural conditions was probably very low. However, extraction with DTPA generated significant amounts of metals (mainly Pb and Cu), suggesting they were potentially mobilizable. A botanical survey of the area showed a biodiverse plant community (28 species and 11 families), with no obvious toxicity symptoms. Measurements of metal contents in dominant species confirmed that they were closely similar to those reported for species growing in unpolluted environments. Consequently, for an effective site restoration, indigenous species could be well suited to cope with local conditions in a phytostabilization strategy.

Typing of murine cell-surface antigens by cellular radioimmunoassay.

A cellular radioimmunoassay utilizing 125I-labelled Protein A was used for detecting antigen-antibody complexes on glutaraldehyde fixed cells attached to microtiter plates. This method is rapid, sensitive and specific for revealing H-2 private and public specificities as well as Ia and Lyt antigens. As plates may be kept for months, several reactivities can be tested in one step on a large panel rendering a regular supply of animals unnecessary.

[Epithelioid renal angiomyolipoma: benign or malignant tumor?]. / L'angiomyolipome rénal épithélioïde: tumeur bénigne ou maligne?

Angiomyolipoma is a well-known rare soft tissue tumor involving the kidneys, liver and other organs. Long believed to be a benign hamartoma, angiomyolipoma is now considered a neoplasm that arises from perivascular epithelioid cell. Epithelioid angiomyolipoma is a rare variant of angiomyolipoma characterized by epithelioid cells that mimic renal cell carcinoma and is potentially malignant. Immunoreactivity with HMB45 is helpful for its identification. We report the computed tomographic and histologic findings in a 36 years old woman with epithelioid angiomyolipoma and lymph node involvement.

[MRI of portal cavernoma with biliary involvement]. / IRM des cavernomes portaux à retentissement biliaire.

PURPOSE: To assess the value of MRI in the diagnosis of portal cavernoma with biliary obstruction. MATERIAL: and methods: six patients referred for clinical suspicion of biliary obstruction and portal cavernoma were explored with MRI. all patients were explored using a signa 1.5 t GE MR unit, with high gradient field strength and torso phased array coil. Biliary ducts were explored with ss-fse sequences of MR-cholangiopancreatography (MRCP), coronal and oblique coronal 20mm thick slices. Then, coronal T2w with shorter TE eff, MR-angiography and delayed T1w sequences were performed. CT scan and sonographic examinations of the liver were performed in all patients. Two patients were operated on and 2 underwent endoscopic retrograde cholangiography. RESULTS: Three different types of biliary involvement were found: in 3 cases findings that mimic cholangiocarcinoma spreading along the common bile duct and in 3 other cases multiple smooth extrinsic impressions along the common bile duct; in one patient MRCP demonstrated an irregular narrowing of the common bile duct mimicking chronic cholangitis. In all cases, the bile duct varices appeared of low T2W signal; in three cases, fibrosis was identified on delayed sequences. CONCLUSION: MRCP and MR-angiography can be proposed as a first imaging study in patients with portal cavernoma and cholestasis or bile duct dilatation.

[Secondary diseases of the peritoneum]. / Le péritoine << témoin >> de la pathologie abdomino-pelvienne.

Most inflammatory, infectious or tumoral diseases of the bowel and abdominal organs may secondarily involve the peritoneum which acts as a mirror of the diseases. Multidetector CT allows breathhold acquisitions through the abdomen and pelvis providing high spatial and contrast resolution imaging at all phases of contrast distribution as well as MPR and 3D capabilities.

[Incremental lower extremity CT venography, a simplified approach for the diagnosis of phlebitis in patients with pulmonary embolism]. / Phlébotomodensitométrie incrémentale des membres inférieurs, une approche simplifiée du diagnostic de la phlébite au cours des embolies pulmonaires.

PURPOSE: To demonstrate that incremental CT venography, performed at the time of CT pulmonary angiography, can easily diagnose deep venous thrombosis. Materials and Methods. Retrospective analysis of 152 combined incremental CT venography and CT pulmonary angiography. Results were compared to Doppler US examinations in 18 cases. RESULTS: 61% of venous thrombosis was found on incremental CT examination in case of pulmonary embolism. In 5 cases, isolated venous thrombosis was found without pulmonary embolism. The CT diagnosis of DVT was confirmed by US; CT appeared more accurate than US in the calf. CONCLUSION: CT venography combined with CT pulmonary angiography is a useful tool in order to obtain a comprehensive evaluation for thrombo-embolic disease.

[Pneumobilia and MRCP: value of sagittal view]. / Aérobilie et cp-irm: intérêt des coupes sagittales.

Pneumobilia can lead to artifacts at MRCP obtained from thick coronal and coronal oblique slabs. Axial and sagittal images can both show gas bubbles in bile ducts but sagittal images depict more easily the presence of an air-fluid level.

[Imaging of the intrahepatic biliary tree with thick slice MR cholangiography]. / Imagerie des voies biliaires intrahépatiques en cholangiographie-IRM en coupes épaisses.

PURPOSE: To assess the value of single shot fast spin echo MR sequence (SS-FSE) in the evaluation of the normal and pathologic intrahepatic biliary tree. MATERIAL AND METHODS: 418 consecutive patients (457 examinations) referred for clinical and/or biological suspicion of biliary obstruction underwent MR cholangiopancreatography (MRCP). All patients were imaged with a Signa 1.5 T GE MR unit, with High Gradient Field Strength and Torso Phased Array Coil. Biliary ducts were imaged with SS-FSE sequence, coronal and oblique coronal 20 mm thick slices on a 256 x 256 matrix. Total acquisition time was 1 second. Source images were reviewed by two radiologists blinded to clinical information. In case of disagreement, a third radiologist's opinion was requested. In all cases, MRCP results were compared with direct biliary tract evaluation, other imaging studies and clinical and biological follow-up. RESULTS: In all cases, MRCP produced high quality images. Numerous branch of division were observed although the peripheral intrahepatic ducts were well seen in more than 90% in an area 2 cm below the capsule. The number of division was statistically higher when mechanical obstruction was present. Intrahepatic calculi or peripheral cholangiocarcinoma were well detect by MRCP. For the detection of cholangitis, MRCP sensitivity was 87.5% but the positive predictive value was only 57.7% because of a high number of false positive. The diagnosis of primary sclerosing cholangitis must be made only on strict criteria and slightly dilated peripheral bile ducts unconnected to the central ducts in several hepatic segments were a characteristic MR sign of primary sclerosing cholangitis. CONCLUSION: MRCP can be proposed as a first intention imaging technique for the evaluation of intrahepatic ducts.