Impregnation of Scots pine and beech with tannin solutions: effect of viscosity and wood anatomy in wood infiltration

The impregnation process of Scots pine and beech samples with tannin solutions was investigated. The two materials involved in the process (impregnation solution and wood samples) are studied in depth. Viscosity of mimosa tannin solutions and the anatomical aspect of beech and Scots pine were analysed and correlated. The viscosity of tannin solutions presents a non-newtonian behaviour when its pH level increases, and in the case of addition of hexamine as a hardener, the crosslinking of the flavonoids turns out to be of great importance. During the impregnation of Scots pine (Pinus sylvestris L.) and beech (Fagus sylvatica L.), the liquid and solid uptakes were monitored while taking into consideration the different conditions of the impregnation process. This method allowed to identify the best conditions needed in order to get a successful preservative uptake for each wooden substrate. The penetration mechanism within the wood of both species was revealed with the aid of a microscopic analysis. Scots pine is impregnated through the tracheids in the longitudinal direction and through parenchyma rays in the radial direction, whereas in beech, the penetration occurs almost completely through longitudinal vessels.

[Bipolar electrocoagulation of red spider veins and telangiectasis of the face]

The development of a patented bipolar "coagulation fork", applied in combination with a customized microprocessor-controlled high-frequency unit, constitutes a break-through in the treatment of very small varicose veins of less than 0.5 mm in diameter, commonly described as spider veins, that cannot be removed through sclerotherapy. The technique is quite simple and does not require any kind of anesthesia. It is also best suited to treat teleangiectases on the face. Follow-up treatment is not required.

Mechanical alterations in smooth muscle from mice lacking desmin

Mice with a null mutation introduced in the desmin gene were used to study the mechanical role of intermediate filaments in smooth muscle cells. Vas deferens (VD), urinary bladder (UB) and portal vein (PV) preparations were obtained from adult animals lacking desmin (Des -/-) and from age- and weight-matched wild-type animals (Des +/+). Active force per cross-sectional area was decreased in the smooth muscle of the Des -/- compared with Des +/+ mice (VD to 42%; UB to 34%). Quantitative gel electrophoresis suggests a marginally lower cellular content of myosin, but the organization of the contractile apparatus appeared unchanged by electron microscopy. A similar reduction in stress was measured in Des -/- skinned fibres showing that altered activation mechanisms were not involved. The results indicate that the reduced active force is caused by low intrinsic force generation of the contractile filaments or subtle modifications in the coupling between the contractile elements and the cytoskeleton. The relationship between length and passive stress was less steep in the Des -/- samples and a second length force curve after maximal extension revealed a loss of passive stress. The maximal shortening velocity was reduced in Des -/- skinned VD and UB preparations by approximately 25-40%. This was associated with an increased relative content of the basic essential myosin light chain, suggesting that alterations in the contractile system towards a slower, more economical muscle had occurred. PV preparations showed no difference in mechanical properties in Des +/+ and Des -/- animals, a result that was consistent with the predominance of vimentin instead of desmin in this vascular tissue. In conclusion, the results show that, although intermediate filaments in smooth muscle are not required for force generation or maintenance of passive tension, they have a role in cellular transmission of both active and passive force.

Localization of smoothelin in avian smooth muscle and identification of a vascular-specific isoform

Smoothelin is a smooth muscle-specific protein of minor abundance first identified via a monoclonal antibody obtained using an avian gizzard extract as antigen. Dual labelling of ultrathin sections with antibodies to smoothelin together with antibodies to other smooth muscle proteins showed that smoothelin was co-distributed with filamin and desmin in the cytoskeleton domain of the smooth muscle cell. From the finding that smoothelin, unlike desmin, was readily extracted by Triton X-100 as well as under conditions that solubilized myosin, beta-actin and filamin, we conclude that smoothelin is most likely associated with the actin cytoskeleton. Western blot analysis of gizzard smooth muscle tissue revealed an immunoreactive protein band with an apparent molecular weight of 59 kDa that separated into 3-4 isolated variants, while avian vascular muscle showed a polypeptide band of 95 kDa. These results point to the presence of specific isoforms in visceral and vascular smooth muscles. The 59 kDa isoform was shown to be distinct from the 60 kDa filamin-binding protein, described by Maekawa and Sakai (FEBS Lett. 221, 68-72, 1987). As compared to other smooth muscle markers, such as calponin and SM22, smoothelin appeared very late during differentiation in the chick gizzard, on about the 18th embryonic day.

The Structure Determination of Simonyellin—a New Lichen Naphthopyran

The structure of simonyellin (5,9-dihydroxy-4-methoxy-7-methyl-1H,6H-naphtho[1,8-cd]pyran-1,6-dione), a naphthopyran from the lichen Simonyella variegata Steiner, has been established by X-ray structure analysis of a corresponding tetraacetate derivative. Crystals of simonyellin tetraacetate are triclinic, Pī, a 10.974(2), b 11.282(3), c 20.634(3)Ǻ, α 92.23(2)°, β 100.03(1)°, γ 117.80(2)°; Z 4. Refinement of 2754 data with I > 3σ(I) gave conventional R factors of 0.043 and 0.034.