Ceramide induces activation of the mitochondrial/caspases pathway in Jurkat and SCC61 cells sensitive to gamma-radiation but activation of this sequence is defective in radioresistant SQ20B cells.

Purpose: To clarify the molecular mechanisms leading to radiation-induced apoptosis or resistance, the kinetics (1-48 h) and sequence of events triggered in response to 10 Gy irradiation were investigated in three cell lines displaying a gradient of sensitivity to 7-rays.

Materials And Methods: Ceramide levels were measured by high performance liquid chromatography (HPLC). Mitochondrial function was evaluated in terms of transmembrane potential (delta(psi)m), reactive oxygen species (ROS) and glutathione levels analysed by flow cytometry or HPLC.

Comparison of methods used to study cell death in an adherent tumoral cell line with moderate clonogenic radiosensitivity.

Our objective was to compare different methods for studying programmed cell death in adherent H460 non-small lung cancer cells of moderate clonogenic radiosensitivity. The major effect of gamma-radiation was found to be the release of cells from the substratum. The different methods gave complementary and unexpected information: a) with the TUNEL method, a few non-apoptotic cells were found in the culture medium; b) with the flow cytometry after propidium iodide labeling, some hypodiploid cells which remained attached to the substratum were apoptotic, as demonstrated by the effect of a caspase inhibitor; c) with the annexin V labeling, the detached cells were demonstrated either necrotic or very late apoptotic; d) the mitochondria transmembrane potential (deltapsim), measurements demonstrated that the mitochondria were implicated in cell death induced by gamma-radiation.

Temporal relationships between ceramide production, caspase activation and mitochondrial dysfunction in cell lines with varying sensitivity to anti-Fas-induced apoptosis.

To clarify the chronology of events leading to anti-Fas-induced apoptosis, and the mechanisms of resistance to this death effector, we compared the response kinetics of three tumour cell lines that display varying sensitivity to anti-Fas (based on levels of apoptosis), in terms of ceramide release, mitochondrial function and the caspase-activation pathway. In the highly sensitive Jurkat cell line, early caspase-8 activation, observed from 2 h after treatment, was chronologically associated with an acute depletion of glutathione and the cleavage of caspase-3 and poly-ADP ribosyl polymerase (PARP), followed by a progressive fall in the mitochondrial transmembrane potential (Delta(psi)m), between 4 and 48 h after treatment. Ceramide levels began to increase 2 h after the addition of anti-Fas (with no increase during the first hour), and increased continuously to 640% of control cells at 48 h.

Risk factors influencing the outcome of portal and mesenteric vein thrombosis.

Background/aims: This study analyzes risk factors that influence the course and outcome of portal and superior mesenteric vein thrombosis (PMVT).

Methodology: We retrospectively reviewed 45 patients who were admitted to our institution over a 17-year period with a diagnosis of PMVT. Patients were classified according to three etiological groups, namely: cirrhosis (47%), pancreatitis (22%), and other causes (33%), with 1 patient belonging to two different groups.

Study of O-sialylation of glycoproteins in C6 glioma cells treated with retinoic acid.

When treated with retinoic acid in vivo, C6 glioma cells show an enhancement of CMP-Neu5Ac:Gal beta 1-3 GalNAc-R alpha-2,3 sialyltransferase activity. A 300 kDa glycoprotein was detected by lectin affinoblotting in retinoic acid-treated C6 cells which stained weakly or not at all in control cells. Comparative studies with different lectins demonstrated that this glycoprotein contains alpha 2,3 Neu5Ac Gal-GalNAc O-glycan moieties.

Study of retinoic acid effect upon retinoic acid receptors beta (RAR-beta) in C6 cultured glioma cells.

Using monoclonal antibodies against the RAR-alpha and RAR-beta retinoic receptors, we demonstrated that these receptors were present together in C6 glioma cells as two isoforms of 50 and 55 kDa. For RAR-beta, the 50 kDa isoform predominated (60 to 80% of the total of the two isoforms). After a treatment for 48 h with retinoic acid 10 microM, the 55 kDa form was enhanced, while no effect was observed either on RAR-alpha isoforms from C6 cells and on both RAR-alpha and RAR-beta forms from neuroblastoma SKN SH SY5Y used as a control.

[Serum phospholipase A2 activity in osteoarthritis].

Serum phospholipase A2 activity in 67 osteoarthritis patients and 17 controls was determined using a radiolabeled specific substrate. Serum phospholipase A2 activity was significantly higher in osteoarthritis patients (115 +/- 73.6 dpm/h/ml) than in controls (45 +/- 25 dpm/h/ml) (p = 0.

Fat embolism syndrome.

Twenty cases of clinically patent fat embolism syndrome (FES) were observed at the authors' institution between 1964 and 1989. There were 4 deaths (20%). The injury severity score (ISS) was computed for each patient upon admission and ranged from 9 to 50 (median, 17).

Colon carcinoma immunoscintigraphy by monoclonal anti-CEA antibody labeled with gallium-67-aminooxyacetyldeferroxamine.

Previous experimental results in nude mice showing that radiolabeling the monoclonal antibody anti-CEA 35 with 67Ga-aminooxyacetyldeferroxamine could give better tumor localization than radioiodination prompted us to initiate the present clinical study. The 67Ga-labeled antibody anti-CEA 35 (185 MBq, 0.7-1.

Study of O-glycan sialylation in C6 cultured glioma cells: regulation of a beta-galactoside alpha 2,3 sialyltransferase activity by Ca2+/calmodulin antagonists and phosphatase inhibitors.

We have demonstrated that the alpha 2,3 sialyltransferase (alpha 2,3 ST) from C6 cultured glioma cells was inhibited in vivo by W-7 and related Ca2+/Calmodulin (Ca/CaM) antagonists while protein kinase C effectors had no effect. Dephosphorylation of alpha 2,3 ST by the wide specificity alkaline phosphatase led to inactivation indicating that the enzyme is phosphorylated. The serine/threonine protein phosphatase inhibitors okadaic acid and Calyculin A led also to an inhibition of alpha 2,3 ST activity.

[Perforation of gastric ulcer in inguinal hernia].

We report about a case of perforation of a peptic ulcer in an inguinal hernia. A 64-year-old female patient had been suffering from bilateral inguinal hernias for several years, without digestive complaints. The sudden occurrence of symptoms resulted not from strangulation, but from a specific complication of the incarcerated organ, ie.

Effect of non-steroidal anti-inflammatory drugs (NSAIDS) on glycosyltransferase activity from human osteoarthritic cartilage.

The effect of non-steroidal anti-inflammatory drugs (NSAIDs) on the activity of glycosyltransferases required for the synthesis of the polysaccharide chains of proteoglycans, was studied in human osteoarthritic cartilage in vitro. Using exogenous acceptors, salicylate and indomethacin suppressed the activity of glucuronyl- and xylosyltransferases in a concentration-dependent manner, but had little effect on N-acetylgalactosaminyl- and galactosyltransferases. When used at a concentration derived from the values found in the synovial fluid, salicylate, indomethacin and chloroquine significantly suppressed the activity of glucuronyl- and xylosyltransferases, while tiaprofenic acid, paracetamol (acetaminophen), floctafenine, ketoprofen, ibuprofen and tenoxicam had no effect on the enzymes.

Study of O-glycan sialylation in C6 cultured glioma cells: evidence for post-translational regulation of a beta-galactoside alpha 2,3 sialyltransferase activity by N-glycosylation.

We have studied the Gal beta 1-3GalNAc-R alpha 2,3 sialyltransferase from C6 glioma cells transferring Neu5Ac from CMP-Neu5Ac onto O-glycans of glycoproteins. Using synchronized C6 glioma cells, we showed that the alpha 2,3 sialyltransferase activity was inhibited by tunicamycin to a greater extend than DNA and protein biosynthesis suggesting inhibition of N-glycosylation of this enzyme. Additional demonstration of N-glycosylation of the alpha 2,3 sialytransferase was provided through ConA-Sepharose binding.

[Cytokines, prostaglandin E2, phospholipase A and metalloproteases in synovial fluid in osteoarthritis].

Concentrations of prostaglandin E2, interleukin 1 beta, interleukin 6 and tumor necrosis factor alpha, phospholipase A2, collagenase and proteoglycanase activity were determined in synovial fluid from 26 patients with osteoarthrosis of the knee and 10 with rheumatoid arthritis. Osteoarthrosis synovial fluid was characterised by the absence of interleukin 1 beta while tumour necrosis factor alpha and interleukin 6 were present in relatively large amounts, by a very high phospholipase A2 activity contrasting with a very low concentration of prostaglandin E2, and by a collagenase/proteoglycanase activity only slightly less constant and high as in rheumatoid arthritis. In osteoarthrosis patients, the interleukin 6 concentration, but not that of tumor necrosis factor alpha, was correlated with the collagenase and proteoglycanase activity of synovial fluid.

Calmodulin-dependent collagenase and proteoglycanase activities in chondrocytes from human osteoarthritic cartilage.

Chondrocyte metalloproteinases appear to play a major role in the development of osteoarthritis. The intracellular post-traductional mechanisms regulating collagenase and proteoglycanase are not known. Calmodulin antagonists including phenothiazine and sulfonamide derivatives significantly increased proteoglycanase activity and decreased collagenase activity.

Serotonin-stimulated phospholipase A2 and collagenase activation in chondrocytes from human osteoarthritic articular cartilage.

We have previously described several receptors on the chondrocyte membrane. In an attempt to further characterize the coupling mechanisms of serotoninergic receptors, here we examined the involvement of serotonin in the phospholipase A2 activity. Serotonin dose-dependently stimulated phospholipase A2.

Glycosyltransferase activities in chondrocytes from osteoarthritic and normal human articular cartilage.

Six glycosyltransferases (mannosyl-, glucosyl-, N-acetyl-glucosaminyl-, galactosyl-, sialyl- and fucosyltransferases) are studied and characterized for their optimal conditions and their relations with interfering reactions (glycosyl-nucleotide pyrophosphatases, glycosidases and proteinases) in chondrocytes from osteoarthritic and normal human articular cartilage. Osteoarthritis induces increased activities for five glycosyl-transferases. The observed modifications are not explained by alterations in physico-chemical parameters of the enzymes or by intervention of glycosyl-nucleotide pyrophosphatases, glycosidases or proteolytic enzymes.

Cartilage degradative enzymes in human osteoarthritis: effect of a nonsteroidal antiinflammatory drug administered orally.

The activity of stromelysin and collagenase was determined in fibrillated human OA cartilage using labeled proteoglycans and type II collagen as substrates. In vitro paracetamol had no effect on metalloprotease whereas TA induced a significant inhibition of stromelysin. In cartilage and synovium from nine patients treated with TA and nine patients treated with paracetamol during 8 weeks before surgery for hip OA, stromelysin activity was significantly lower in the TA than in the paracetamol group.

Effect of desipramine on a glycoprotein sialyltransferase activity in C6 cultured glioma cells.

The tricyclic antidepressant desipramine, when added to culture medium, gave rise in C6 rat glioma cells to a decrease of the activity of the enzyme asialofetuin sialyltransferase. The inhibition was dose and time dependent and was observed in both multiplying cells and cells blocked with 2 mM thymidine or depletion of amino acids. This inhibition was rather specific to the sialyltransferase, as under the conditions where this enzyme was inhibited up to 70%, other enzymes such as dolichol phosphate mannose synthetase, glutamine synthetase, and glycerol phosphate dehydrogenase remained unaffected.

Histaminergic H1, serotoninergic, beta adrenergic and dopaminergic receptors in human osteoarthritic cartilage.

Using radioligand binding assays, histaminergic H1, serotoninergic, dopaminergic and Beta adrenergic receptors were studied in human normal and osteoarthritic cartilage. The four studied receptors were present in normal cartilage; serotoninergic, dopaminergic and Beta adrenergic receptors were significantly increased in osteoarthritic cartilage while histaminergic H1 receptors were significantly increased only in osteophytic cartilage. The results are consistent with a non specific activation of osteoarthritic chondrocytes.

Effect of retinoic acid on two glycosyltransferase activities in C6 cultured glioma cells.

1. Activity of two glycosyltransferases was studied in retinoic acid-treated C6 cultured glioma cells. 2.

Evidence for an O-glycan sialylation system in brain. Characterization of a beta-galactoside alpha 2,3-sialyltransferase from rat brain regulating the expression of an alpha-N-acetylgalactosaminide alpha 2,6-sialyltransferase activity.

We present evidence for the existence in rat brain of several sialyltransferases able to sialylate sequentially asialofetuin. [14C]Sialylated glycans of asialofetuin were analyzed by gel filtration. Three types of [14C]sialylated glycans were synthesized: N-glycans and monosialylated and disialylated O-glycans.