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A new composite scaffold containing type I collagen, hyaluronan, and fibrin was prepared with and without autologous chondrocytes and implanted into a rabbit femoral trochlea. The biophysical properties of the composite scaffold were similar to native cartilage. The macroscopic, histological, and immunohistochemical analysis of the regenerated tissue from cell-seeded scaffolds was performed 6 weeks after the implantation and predominantly showed formation of hyaline cartilage accompanied by production of glycosaminoglycans and type II collagen with minor fibro-cartilage production. Implanted scaffolds without cells healed predominantly as fibro-cartilage, although glycosaminoglycans and type II collagen, which form hyaline cartilage, were also observed. On the other hand, fibro-cartilage or fibrous tissue or both were only formed in the defects without scaffold. The new composite scaffold containing collagen type I, hyaluronan, and fibrin, seeded with autologous chondrocytes and implanted into rabbit femoral trochlea, was found to be highly effective in cartilage repair after only 6 weeks. The new composite scaffold can therefore enhance cartilage regeneration of osteochondral defects, by the supporting of the hyaline cartilage formation.

Electromagnetic activity around yeast mitotic cells (Saccharomyces cerevisiae) was measured in the frequency range 8-9 MHz and special care was taken to extract reliable information from the raw signals. The characteristic of cold-sensitive tubulin mutants tub2-401 and tub2-406, which come to arrest before mitosis at a restrictive temperature (14°C) and which re-enter mitosis upon a shift back to a permissive temperature (28°C), was used to prepare synchronized mitotic cells. Immunofluorescence microscopy using an antitubulin antibody was used to analyze microtubular structures. The arrested tub2-401 mutant that had back-shifted to permissive temperature displayed no microtubules and no electromagnetic activity around the cells. In contrast, the arrested cells of the mutant tub2-406 displayed developed, but aberrant, nonfunctional microtubules and a high electromagnetic activity around the cells. The electromagnetic activity around the arrested mutant tub2-401 backshifted to permissive temperature peaks at four time points which may coincide with (i) formation of the mitotic spindle, (ii) binding of chromatids to kinetochore microtubules, (iii) elongation of the spindle in anaphase A, and (iv) elongation of the spindle in anaphase B. The profile of the electromagnetic * Corresponding Electromagn Biol Med Downloaded from informahealthcare.com by CDL-UC San Diego on 06/03/15For personal use only. ORDER REPRINTS 372POKORNÝ ET AL.activity around the synchronized mutant tub2-406 at permissive temperature seems to be delayed by the time required for aberrant nonfunctional microtubules to be depolymerized. Experimental results presented in this paper support Pohl's idea of existence of the electromagnetic field around yeast cells.

Abstract. Biological polar molecules and polymer structures with energy supply (such as microtubules in the cytoskeleton) can get excited and generate an endogenous electromagnetic field with strong electrical component in their vicinity. The endogenous electrical fields through action on charges, on dipoles and multipoles, and through polarization (causing dielectrophoretic effect) exert forces and can drive charges and particles in the cell. The transport of mass particles and electrons is analyzed as a Wiener-Lévy process with inclusion of deterministic force (validity of the Bloch theorem is assumed for transport of electrons in molecular chains too). We compare transport driven by deterministic forces (together with an inseparable thermal component) with that driven thermally and evaluate the probability to reach the target. Deterministic forces can transport particles and electrons with higher probability than forces of thermal origin only. The effect of deterministic forces on directed transport is dominant.

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Vibrations in microtubules and actin filaments are analysed using amethod similar to that employed for description of lattice vibrationsin solid state physics. The derived dispersion relations show thatvibrations in microtubules can have optical and acoustical branches.The highest frequency of vibrations in microtubules and in actinfilaments is of the order of 10(8) Hz. Vibrations are polar andinteraction with surroundings is mediated by the generatedelectromagnetic field. Supply of energy from hydrolysis of guanosinetriphosphate (GTP) in microtubules and of adenosine triphosphate(ATP) in actin filaments may excite the vibrations.

Jelínek F.: Spontaneous Tumours in Guinea Pigs. Acta Vet. Brno 2003, 72: 221-228.The aim of the study is to describe spontaneous tumours in guinea pigs. Twenty neoplasias from 19 guinea pigs were examined histologically. In 15 cases biopsy samples were examined, samples from four animals were collected during autopsy. Except for one, all animals were kept as pets. Skin tumours were diagnosed in five of them. They appeared in different locations -abdomen, plantar side of hind leg, back (in two animals), and rump, and were of different sizes, the largest one was five cm in diameter. All tumours were of follicular origin -two trichofolliculomas, two trichoepitheliomas, one malignant pilomatricoma. The age of affected animals ranged from two to 7.5 years. Tumours of the mammary gland were present in five guinea pigs. Adenocarcinoma was diagnosed in two males, sarcoma of myoepithelial origin was found in one female. Tubular adenoma was present in one two-yearold female, and adenomatous hyperplasia of the mammary gland was observed in another female of the same age. In six guinea pigs, three females and three males, between three and five years of age, there were tumours in subcutaneous tissue. Three were lipomas, in one animal the lipoma was multiple. Liposarcoma was found in one male, myxoid liposarcoma was diagnosed in another one. Ossifying fibroma was histologically diagnosed in one female. Lymphatic leukaemia was observed in three males. All animals were 4-year-old. Hepatocellular adenoma was found in a 5-year-old female suffering also from trichofolliculoma as mentioned above. Data about tumours in guinea pigs are relatively rare, and therefore information along this line is useful both for clinical practice and comparative pathology.

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