Variability of the biological activity of oxidized titanium implants.

Oxidized titanium is a biologically inert material, but bioinertness reduces biomechanical characteristics of titanium implants. Modification of the structure of oxide surface layer of BT 5-1 titanium by increasing its thickness (by 1.7 times) and pore diameter (by 1.4 times) and by adding phosphorus, aluminum, and zinc oxides to its composition leads to radical modification of its biological characteristics. These implants acquire osteoinductive properties in in vivo systems not found in pure or oxidized BT 1-00 titanium and fairly well maintain in vitro growth of mesenchymal cells.

Acupuncture muscle channel in the subcutaneous layer of rat skin.

Using a mixed-dye injection technique, we found a novel kind of muscle fiber with a lumen, established its precise location in the subcutaneous muscle layer along the acupuncture muscle of the bladder line, and determined its detailed ultrastructure. The channels with flowing liquid were a novel kind of muscle fibers with lumens and they were located in the subcutaneous muscle layer of rat. Their detection was realized by using chrome-hematoxylin and a mixture of fluorescent nanoparticles and commercial Pelikan ink. These acupuncture muscle channels were hidden among the neighboring skin skeletal muscle fibers and were barely distinguishable from them with light microscopes. Only with a transmission electron microscope were their characteristic features shown to be different from normal skin skeletal muscle. These features included undifferentiated muscle fibers that resembled immature myofibrils without Z-lines and reassembled telophase nuclei.

A 'biorelevant' system to investigate in vitro drug released from a naltrexone implant.

This research is based on the recognized need for an in vitro release method for drug implants that better simulate physiological conditions at the site of implantation ('biorelevance'). In this paper, we describe the evaluation of a 'biorelevant' approach for in vitro drug release testing of a biodegradable implant of naltrexone in a pre-clinical stage of development. A miniature, capillary cell culture device was modified and tested as a biorelevant alternative for a standard commercially available flow-through cell. The real-time data generated through 90 days indicated a 48% lower rate of release for the capillary system. The profiles using both systems followed zero-order kinetics after an initial period of burst release. In vitro release data from the capillary device resulted in a 1-to-1 correlation with dog plasma pharmacokinetic data, and furthermore, the capillary device potentially simulated the lag-time in absorption more effectively than the flow-through cell. Scanning electron micrographs revealed that the sheath was continuous with no signs of cracks at the end of in vitro and in vivo studies. However, at the interface of the sheath and the core, intercalating, "finger-like" projections were observed consistent with penetration of the medium. No macroscopic or clinical toxicity signs were observed during the in vivo implantation study.

Modification of skin composition by conjugated linoleic acid alone or with combination of other fatty acids in mice.

The effects of conjugated linoleic acid (CLA), gamma-linolenic acid (GLA), linoleic acid (LA), and their combinations, on skin composition in mice were investigated. Mice (8 weeks old) were orally administered with either LA, GLA, CLA, LA + GLA, LA + CLA, or CLA + GLA for 4 weeks. Then, the skin was analysed for triacylglycerol content, fatty acid composition and collagen content. Additionally, thicknesses of the dermis layer and subcutaneous tissue layer, and the size and number of adipocytes were measured histologically. The skin fatty acid composition was modified depending upon the fatty acid composition of supplemented oils. In each oil-alone group, skin triacylglycerol content was the highest in LA, followed by GLA and CLA treatments. Combinations with CLA had a similar triacylglycerol content compared with the CLA-alone group. No significant changes in collagen content were observed among any treatments. The effects on subcutaneous thickness were similar to the results obtained in the triacylglycerol contents, where groups supplemented with CLA alone or other fatty acids had significantly thinner subcutaneous tissue compared with the LA-alone group. However, no significant difference was detected in the thickness of the dermis layers. The number of adipocytes was highest in the LA + GLA group and tended to be reduced by CLA with or without the other fatty acids. These results suggest that CLA alone or in combination with other fatty acids strongly modifies skin composition in mice.

Dietary CLA and DHA modify skin properties in mice.

This study investigated the influence of PUFA on the properties of mouse skin. Mice (3 wk old) were given free access to oils high in linoleic acid, CLA, or DHA for 4 wk. At the end of the experiment, their skins were compared by both biochemical and histological methods. No significant differences in lipid and collagen contents were detected among treatments, although the FA composition in the skin was altered depending upon the FA composition of the supplemented oils. Electron microscopy revealed that the subcutaneous tissue layers in the CLA and DHA groups were significantly thinner than that in the high linoleic acid group, whereas no differences in the thickness of dermis layers were observed among the three groups. These results suggest that skin properties in mice are readily modified by dietary FA sources within 4 wk of dietary oil supplementation.

[Ultrastructural changes of collagen fibrils in mouse dermal connective tissue after moxibustion treatment].

Morphological changes in mouse back skin, especially dermal connective tissue, were observed after moxibustion treatment. Various amounts of direct moxibustion and indirect moxibustion (column) were performed and the exact skin area was processed for light and electron microscopy. Just after treatment, epidermal cell layer was degenerated and increased amounts of mast cells were observed. Many unwinding collagen fibrils were prominent. Twenty-four hours after treatment, the number of unwinding fibrils decreased. Instead, tightly winding fibrils, sometimes thicker, were observed in a similar area. D-period of collagen fibrils did not change in any situation. Physical reaction to moxibustion varies depending on stimulation rate and/or approach, which includes the change of interstitial connective tissues as well as cellular profiles. It is also important to survey the time-dependent changes in moxibustion treatment.