A new model system for lipid interactions in stratum corneum vesicles: effects of lipid composition, calcium, and pH

We prepared large unilamellar vesicles (LUVs) with three different stratum corneum lipid compositions: constant amounts of ceramides (55 wt %) and fatty acids (15%) with varying amounts of cholesterol sulfate (0-15%) and cholesterol (15-30%). One of the compositions served as a model for normal stratum corneum, while the second one served as a model for recessive X-linked ichthyosis stratum corneum. The third composition consisted of no cholesterol sulfate. Intervesicle lipid interactions in these LUVs were monitored by fluorescence methods for content leakage, and contents mixing at pH 9, in the absence and presence of Ca2+, and at pH 6. Since the content leakage and contents mixing assays were originally developed for phospholipid vesicles, we characterized the probe binding and the probe quenching properties for stratum corneum LUV systems, and modified the assays slightly accordingly. The time-dependent fluorescence intensity changes in the probe-containing LUVs at pH 9 and 6 and in response to the addition of calcium were monitored. Our results demonstrated that all three types of LUVs were relatively stable at pH 9. Addition of Ca2+ or decreasing the pH to 6 activated intervesicle lipid mixing followed by vesicle fusion and lysis. We found that the LUVs with no cholesterol sulfate and 30% cholesterol exhibited a more extensive Ca2+- or low-pH-activated intervesicle lipid interaction than LUVs with either 5% cholesterol sulfate and 25% cholesterol or 15% cholesterol sulfate and 15% cholesterol. These results suggest that fusogenic agents such as Ca2+ and H+ act to neutralize the fatty acids in the lipid bilayer of stratum corneum vesicles. The inclusion of 5-15% cholesterol sulfate helps to prevent the collapse of fused vesicles into other structures.     

A view from the family: years after a loved one has died of ovarian cancer

BACKGROUND: Macrosclerotherapy in combination with compression has proven to be safe and effective in the treatment of varicose veins. Local compression is increased by pads, according to Laplace law. Firm rolls of cotton wool are fixed over the course of the entire vein to increase local compression and to reduce complications. Additional compression is given by a combination of a class I (daytime and nighttime) and class II (daytime only) medical compression hosiery. PURPOSE: To evaluate the effectiveness and side effects of sclerocompression therapy with cotton wool rolls in combination with medical compression hosiery. METHOD: Prospective study with 100 patients (120 legs) with primary varicose veins, which are treated with polidocanol as sclerosant with the empty vein technique. Immediately after the injection, a long cotton wool roll is placed over the entire vein and fixed. Additional compression is obtained with class I and class II medical compression hosiery. The interface pressure on the skin, just under the cotton wool roll, is measured on 12 legs with the aid of an interface pressure measuring instrument (Oxford Pressure Monitor). RESULTS: Good sclerosing results are obtained in all patients. Side effects are classified as early and late. In 16 patients, minor side effects which needed no treatment are observed. In only 3 cases (2.5%), intravascular blood clots (2) and phlebitis (1) needed incision and expression. The mean interface pressure of all measuring sensors under the cotton wool roll is 84 mm/Hg (68 to 122 mm/Hg). CONCLUSION: This study proves the high effectiveness of a cotton wool roll compression right at the place of treatment. By using these long cotton wool compression rolls, the compression part of sclerocompression therapy becomes more effective and much easier to perform.     

Stable association of PYK2 and p130(Cas) in osteoclasts and their co-localization in the sealing zone

Bone resorption is initiated by osteoclast attachment to the mineralized matrix, cytoskeletal reorganization, cellular polarization, and the formation of the sealing zone. The present study examines the interaction between PYK2 and p130(Cas) (Crk-associated substrate), suggested to be part of the signaling pathway initiated by osteoclast adhesion. Using murine osteoclast-like cells (OCLs) and their mononuclear precursors (pOCs), generated in a co-culture of bone marrow and osteoblastic MB1.8 cells, we show that: 1) p130(Cas) is tyrosine-phosphorylated upon adhesion of pOCs to vitronectin or ligation of beta3 integrins; 2) p130(Cas) colocalizes with PYK2 and the cytoskeletal proteins F-actin, vinculin, and paxillin in the podosomal-rich ring-like structures of OCLs plated on glass and in the sealing zone in actively resorbing OCLs on bone; 3) p130(Cas) and PYK2 form a stable complex in pOCs, independent of tyrosine phosphorylation of either molecule, and this complex is present in Src (-/-) OCLs, in which neither protein is phosphorylated or associated with the osteoclast adhesion structure; 4) the association of p130(Cas) and PYK2 is mediated by the SH3 domain of p130(Cas) and the C-terminal domain of PYK2. These findings suggest that p130(Cas) and its association with PYK2 may play an important role in the adhesion-dependent signaling that leads to cytoskeletal reorganization and formation of the sealing zone during osteoclast activation.     

Quantitation and kinetic properties of hepatic microsomal and recombinant flavin-containing monooxygenases 3 and 5 from humans

For many profoundly hearing-impaired listeners (hearing loss > 90 dB HL) speechreading is the most important means of communication; amplified speech may provide, at best, additional information to speechreading. In order to improve audiovisual communication, three speech pattern elements comprising voice-fundamental frequency (f0), the first formant (F1), and the first and the second formant (F1F2) were presented as supplements to speechreading. A fourth condition consisted of a natural speech supplement, a fifth of speechreading only. Twenty subjects were tested; all audiovisual speech scores were significantly higher than the purely visual scores. Audiovisual scores for amplified, natural speech were significantly higher than those for f0 and F1F2 coded speech. Scores for natural speech and for F1 coded speech were not significantly different. The relations between the increase in audiovisual speech scores over the visual scores and measures of difference limen for frequency (DLf) and gap detection were not clear. The most prominent correlations with the speech scores were found for the DLf at 125 Hz and for gap detection.