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Biomedical subjects

V Ottani

Publications and source records attributed to V Ottani.

At least 19 recordsLinked to original sources
PubMed1994

Uptake and distribution of exogenous CoQ in the mitochondrial fraction of perfused rat liver.

The system of perfusing rat livers has been used to evaluate the uptake and incorporation of liposomal CoQ10 into mitochondria. After 90 minutes of perfusion the cells are strongly enriched in CoQ10 up to levels of the same order of magnitude as CoQ9. Heavy and light mitochondrial crude subcellular fractions, low in CoQ10 in control livers, contain high amounts of the quinone after perfusion; yet the purification of these fractions on a metrizamide gradient reveals that the exogenous quinone is mainly associated with the light mitochondrial subfraction, enriched in lysosomes. An increase of the NAD-dependent glutamate-malate oxidase activity is observed in CoQ10 perfused animals. As the total levels of CoQ9 + CoQ10 in these animals are not significantly modified by the CoQ10 incorporated, the observed higher activity is not ascribable to an integration of exogenous quinone into the ubiquinone pool. An antioxidant effect of extramitochondrial CoQ10 on mitochondrial functions is suggested.

Animals↗
PubMed1991

Calcium phosphate materials containing alumina: Raman spectroscopical, histological, and ultrastructural study.

Variable alumina quantities were added to two types of calcium phosphate materials-hydroxyapatite ceramics with Ca/P = 1.67 and calcium metaphosphate glass with Ca/P = 1--in order to increase their mechanical properties. Raman spectroscopy shows that alumina interacts with the phosphate group of these materials, while thermomechanical analysis shows that their elastic modulus has a value similar to that of bone. Histological sections demonstrate that the surface in close contact with ceramic materials shows a good integration between bone and biomaterial. All ceramic specimens are penetrated by well-stained, presumably glycoprotein, matrix, that consistently forms a thin network in close contact with the implant. After 6 weeks bone growing on both ceramic and glass shows signs of maturation with a lamellar structure and an apparently normal mineralization. In the case of the glass, inside this newly formed bone, were often observed two layers, the internal one showing a well defined lamellar structure.

Aluminum Oxide↗
PubMed1991

Ultrastructure of the bovine nuchal ligament.

Nuchal ligament is composed almost exclusively of elastic fibres and collagen fibrils, interwoven very closely and lying parallel to the main ligament axis. Elastic fibres are very large, straight and roughly cylindrical; the collagenous matrix consists of septa of diminishing size forming a 3-dimensional matrix that envelops fibre bundles as well as individual elastic fibres. In all areas examined, collagen fibrils are of very uniform size and, on replicas, they reveal a spiral subfibrillar arrangement with an inclination angle of 17 degrees. Collagen fibrils appear to adhere to the elastic fibres very closely, conforming to their irregular shape. Sometimes they impinge directly upon the elastic fibres, while in other cases a space is visible between collagen fibrils and elastic fibres that contains a rich fabric of intermediate filaments. The collagen-elastin complex of the ligamentum nuchae may be considered a fibre-reinforced composite material comprising tough fibres immersed in an amorphous elastic matrix. Its mechanical behaviour is the result of the combined properties of its components and their interactions.

Animals↗
PubMed1991

Augmentation of bone repair by pulsed elf magnetic fields in rats.

Tibial osteotomies in rats were exposed for 2, 3, 5 and 8 weeks to a pulsed extremely low frequency magnetic field. The shape of the pulse was a double halfwave (50 Hz, 70 G). The rate of bone healing was evaluated by light and electron microscopy. An increase of bone healing was found in rats treated with magnetic fields persisting throughout the tested time. The accelerated healing process produced a sequence of morphological appearances identical to those of a normal fracture callus being the enhancement of osteogenesis produced by an acceleration of preliminary ossification.

Animals↗
PubMed1990

Subfibrillar architecture and functional properties of collagen: a comparative study in rat tendons.

Collagen fibrils from different rat tendons have been investigated by freeze-fracture and transmission electron microscopy. In all cases, marked differences in both fibril morphology and subfibrillar organisation have been consistently found between the tendon core (composed of large and heterogeneous fibrils comprising tightly-packed, straight, parallel molecules) and sheath (showing small, uniform collagen fibrils with a helical arrangement of the molecules). The bio-mechanical requirements to which these tissues are subjected suggest, as do previous observations on other tissues, that a causal correlation exists between substructure and collagen fibril function.

Animals↗
PubMed1989

Different architectures of the collagen fibril: morphological aspects and functional implications.

Several tissues known to contain collagen fibrils with a 'helical' arrangement were studied by t.e.m. and freeze-fracture. In all the tissues examined, the diameter of the collagen fibrils appeared to be tissue-specific and fairly constant within the same tissue. No statistical differences, on the contrary, were detectable in the coiling angle which appeared similar in all the tissues and independent of both diameter and age of the fibril. Rat tail tendon was also examined under the same technical conditions and showed collagen fibrils of large and very heterogeneous diameter and with a consistent 'straight' arrangement. These data seem to suggest that the 'helical' and 'straight' arrangements may actually identify different types of collagen fibrils. The authors discuss the possible functional significance of these arrangements and present two hypotheses on the three-dimensional structure of the 'helical' fibril.

Animals↗
PubMed1988

Effects of pulsed extremely-low-frequency magnetic fields on skin wounds in the rat.

Rats with skin-wounds surgically created on their backs were exposed immediately after surgery and every 12 h thereafter to pulsed, extremely-low-frequency magnetic fields. The shape of the pulse was a positive triangle (50 Hz, 8 mT peak). The rate of healing of skin wounds was evaluated macroscopically and by light and electron microscopy at 6, 12, 21, and 42 days after the operation. A significant increase in the rate of wound contraction was found in rats treated with magnetic fields. Forty-two days after surgery all treated animals show fully closed wounds, while control rats at the same time intervals still lacked a final 6% of the wound surface to be covered. Treated rats showed earlier cellular organization, collagen formation and maturation, and a very early appearance of newly formed vascular network.

Animals↗
PubMed1984

Pulsed electromagnetic fields increase the rate of rat liver regeneration after partial hepatectomy.

Pulsed extremely low-frequency electromagnetic fields interact with rat liver regeneration following partial hepatectomy when delivered to the rats immediately after the operation and every 12 hr thereafter. This interaction results first in an increased ornithine decarboxylase activity, an enzyme used as an early marker of cell growth. The rate of labeled thymidine incorporation into DNA is also increased by the treatments with magnetic fields during the early phases of liver regeneration. Glycogen depletion and lipid accumulation, two well-known early peculiar phenomena of liver regeneration following partial hepatectomy, are quantitatively decreased by the treatments with electromagnetic fields. The recovery to normal glycogen and lipid contents is completed within 5 days after surgery, instead of 7 days as found in control rats.

Animals↗
PubMed1984

Influence of pulsed electromagnetic fields on regenerating rat liver after partial hepatectomy.

Partially hepatectomised rats have been exposed immediately after surgery and every 12 hours thereafter to pulsed extremely low frequency electromagnetic fields. Stereological analysis performed on electron micrographs has shown that the treatment limits the depletion of liver glycogen found in control untreated rats within the first post-operative day. The massive accumulation of lipid droplets found in control rats is also limited to about one half by exposing the animals to pulsed magnetic fields. The time taken for glycogen and lipid content to recover to values found at zero time decreases from seven to five days in animals undergoing treatment with pulsed electromagnetic fields. The liver wet weight and the total protein content show a pattern of changes which is consistent with the behaviour of glycogen and lipid content. Five days after operation the treated rats reach the values found at zero time, while control animals need seven days to reach the same values.

Animals↗
PubMed1982

[Ultrastructural findings on collagen fibers of tendon sheaths from the rat tail].

Rat tail tendon sheaths have been studied by electron microscopy and freeze-etching techniques. Pictures from thin sections have shown the presence of three different sheaths: a) a sheath commun to all tendons, (paratenon) formed by collagen fibrils differently orientated with a variable diameter (20nm 200nm) b) a specific sheath for every tendon, (peritenoneum) which is composed by different layers: the external ones present collagen fibrils of wide and variable diameter (20nm-200nm). The internal ones present collagen fibrils of uniform and small diameter (50nm-60nm). Between these fibres layers, there is evidence for the presence of fibrocits forming continuous cellular layers. c) a sheath surrounding tendon fascicles, (endotenoneum) formed by small and uniform collagen fibrils and a continuous cellular layers. Replicas of freeze-fractured collagen fibrils having a variable diameter show a straight arrangement of their microfibrils.

Animals↗