Diacylglycerol metabolism attenuates T-cell receptor signaling and alters thymocyte differentiation.

Diacylglycerol (DAG) metabolism has a critical function in Ras-regulated functions in mature T cells, but causal data linking defects in DAG-based signals with altered thymus development are missing. To study the effect of increased DAG metabolism in T-cell development, we engineered a membrane-targeted constitutive active version of DAG kinase-α (DGKα). We show that transgenic expression of constitutive active DGK leads to developmental defects in T cells, with a marked accumulation of immature CD8 thymocytes and a reduction in positive selected populations. These alterations are reflected in the periphery by a CD4/CD8 cell imbalance and general T-cell lymphopenia. The results link DAG metabolism to T-cell homeostasis, and show that correctly controlled generation and consumption of this lipid at the plasma membrane ensure T-cell passage through quality-control checkpoints during differentiation.

[Experience with 25-gauge transconjunctival vitrectomy compared to a 20-gauge system. Analysis of 132 cases]. / Etude comparative de la vitrectomie transconjonctivale sans suture à 25-gauges avec celle à 20-gauges. A propos de 132 interventions.

PURPOSE: The transconjunctival sutureless vitrectomy (TSV 25) is a new technique showing substantial progress. METHODS: A prospective study of 66 eyes of 66 patients who underwent surgical procedures using the transconjunctival standard vitrectomy system (TSV 25), between June 2004 and June 2005. The results were compared with the results in an equivalent population (66 patients) that underwent vitrectomy with a standard 20-gauge system. RESULTS: The most important differences between groups were 1) shorter surgical time in the 25-gauge vitrectomy group than in the 20-gauge group, with a mean time of 28.15+/-5.50 min for group 1 and 44.15+/-5.64 min for group 2 (p<0.001) and 2) lower mean postoperative intraocular tension in the first group of patients: in this group, the intraocular tension before surgery was a mean of 16.27+/-1.76 mmHg, decreasing to 12.17+/-1.36 mmHg, with a posterior increase to normal values of 15.06+/-1.66 mmHg at 7 days after surgery and a mean of 16.10+/-1.51 mmHg at 15 days. This decrease was not observed in the group of patients who underwent 20-gauge vitrectomy surgery. The other postoperative complications were similar in both groups except for four cases of anterior proliferation and two cases of fibrinous uveitis in group 2. CONCLUSION: The transconjunctival sutureless system (TSV 25) decreases surgical time and postoperative inflammation, with optimal postoperative patient comfort, but currently the accurate selection of patients remains important.

[Combined surgery for lens extraction, vitrectomy, and implantation in the diabetic patient using phacoemulsification versus phacofragmentation]. / Chirurgie combinée phacoexérèse, vitrectomie et implantation chez le patient diabétique avec phacoémulsification versus phacophragmentation.

INTRODUCTION: In diabetic patients, we often need to perform cataract and pars plana vitrectomy. Two different techniques are currently valid: 1) phacoemulsification and pars plana vitrectomy and 2)pars plana lensectomy and posterior vitrectomy. METHODS: Retrospective study of two different groups of type 2 diabetic patients: those receiving 1) phacoemulsification and pars plana vitrectomy or 2) pars plana lensectomy and posterior vitrectomy. RESULTS: On statistical analysis there were no differences in complications between the two groups. The effect on visual acuity was similar in both groups. DISCUSSION: The association of cataract surgery and posterior vitrectomy is a valid technique for treating diabetic retinopathy complications. In the present study, the complications of the two techniques were similar, the most important concerning only anterior chamber opening in the first group. CONCLUSION: The two techniques of cataract extraction and pars plana vitrectomy at the same time have no differences in their results and are valid for treatment of diabetic patients.

Effect of lactation stage on the cheesemaking properties of milk and the quality of Saint-Nectaire-type cheese.

Two groups of eight multiparous cows with different calving periods (November or February) were managed in the same way during lactation. During four 4 week experimental periods distributed over 12 months, the cows were fed on a diet composed of hay and concentrate (70:30) in a restricted and controlled amount which varied according to their lactation stage, so as to cover the animals' requirements correctly. The animals' average lactation stage varied according to period from 26 to 298 d. Milk from each group was processed on two occasions during each period to make Saint-Nectaire-type cheese; the cheesemaking conditions were the same throughout. Lactation stage had an important effect on milk fat, protein and calcium contents but not on the casein: protein ratio or phosphorus content. The milk pH and the urea content were higher in late lactation. The calcium concentration of milk was higher in late lactation but the soluble fraction was higher in early lactation. Despite higher protein contents, the maximal firmness of the coagulum of late-lactation milk was not different from that of early or mid-lactation milks. pH was higher in cheeses from late-lactation milks compared with those from early and mid-lactation milks. Cheeses from early lactation milks were more yellow than the others and had a lower dry matter fat content. In sensory analysis the odour of cheeses from early and late-lactation milks was less pleasant than that of those from mid-lactation milks. Cheeses from late-lactation milks were more melting and less firm than those from early or mid-lactation milks. Their taste was more intense and more persistent. At tasting, they were less appreciated than the others. These differences were linked to increased proteolysis in the cheeses made with late-lactation milks.