Osteoid osteoma is a benign bone tumour usually occurring in young individuals (10-30 years). It presents with intense pain (typically nocturnal), which can be alleviated by salicylates. Treatment consists of surgical excision or destroying the nidus and it is curative. In the past, surgery was performed in an "open" fashion and the nidus had to be removed with a bone block. This extensive type of surgery could be associated with some rates of both failure and complication. There is growing evidence to suggest that percutaneous CT-guided removal or destruction of the nidus is a good alternative and it is indeed gaining worldwide popularity. We present a series of 18 consecutive patients with osteoid osteoma of the pelvis, femur, and tibia, treated percutaneously under CT guidance. Removal of the nidus was performed using a 4.5-mm cannulated drill and a cannulated curette of our own design. Tissue samples for histological evaluation were obtained in the same way. The mean follow-up time was 29 months. Sixteen patients were initially cured. The procedure had to be repeated in two patients and was eventually successful (primary and secondary success rates 88 and 100% respectively). The diagnosis was histologically confirmed in 14 cases out of 18 (77%). In four cases no histological confirmation of osteoid osteoma could be achieved. There were only two minor complications, one case of femoral neuropraxia and one case of skin abrasion. Percutaneous CT-guided removal seems to be efficient and safe for the treatment of osteoid osteoma. The use of a cannulated drill and a cannulated curette facilitates efficient removal of the tumour and procurement of tissue for diagnosis.
The efflux of glycerol-SH from mature R. pipiens oocytes was studied by extractive analysis and by quantitative radioautography using techniques suitable for diffusible solutes. Extractive analysis was used to determine the total cellular concentration of tracer, and radioautography, regional intracellular concentrations, at equilibrium and as a function of efftux time, t~. The efflux was resolvable into four kinetic fractions: cytoplasmic fast and slow fractions, and nuclear fast and slow fractions. The fast fractions represent freely diffusible glycerol in the two compartments; the solvent space accessible to glycerol is unity in the nucleus (germinal vesicle), but only 0.73 in the cytoplasm. The efflux of both fast fractions from the cell is determined by the permeability of the cortical membrane, with neither the nuclear membrane nor diffusion in the cytoplasm detectably slowing the flux. The permeability at 13.6°C is 2.2 >( 10 -5 cm/sec. The slow fractions leave the cell at about one-tenth the rate of the fast; the interpretation is that these fractions represent glycerol bound to impermeant cellular constituents. The size of these constituents is below the radioautographic resolution; in the cytoplasm, they appear not to be the yolk platelets. The extent of binding is about fourfold greater, per milliliter of compartment water, in the cytoplasm than in the germinal vesicle.
I N T R O D U C T I O NTransport processes are generally monitored by following the flux of a tracer into, out of, or across a whole cell or a multicellular preparation. This technique has two obvious limitations. First, if complex or "multicompartmental" flux kinetics are found, there is no rigorous way to identify the origins of the contributing terms. Second, there is no way to monitor separately the local transport process in intracellular inclusions of specific interest, such as the nucleus. These limitations can be partly alleviated by studying transport in isolated subcellular preparations, but one is then faced with problems of purification and deterioration, which cannot be controlled by reference to behavior in situ.
It arises from the ability of water to form stabilized structures ("icebergs") through interaction with nonpolar groups and has the effect of selectively slowing the diffusion of solutes bearing such groups. Solute diffusional specificity in water represents a superimposition of these.two processes; additional evidence for this is provided by data on the temperature dependence of diffusion and the correlation of diffusion coefficients with entropies of vaporization.
Background: The purpose of this study is to illustrate the routes of migration of precartilaginous cells from the perichondrial ring of LaCroix, as a potential reservoir for growth-plate germ cells. Methods: Chondrocytes derived from the ring of LaCroix of young chicks' proximal tibia were cultured in vitro and transfected with adenovirus vector containing the gene encoding for Escherichia coli (beta)-galactosidase (lacZ) gene, which allows assessment of the migratory routes of these cells. The lacZ-transfected cells were injected back into the perichondrial ring of LaCroix of young chicks' proximal tibias. Four weeks later the migration root was assessed microscopically. Results: Injection of cells derived from the ring of LaCroix of neonate chicks, transfected in culture with adenoviruses containing LacZ reporter gene, allows the assessment of migratory potential of these cells. Stained cells were found at the outer layer of the epiphysis, particularly in areas adjacent to the perichondrial ring. Further longitudinal histopathological studies along the bone axis demonstrated a condensed layer of the stained cells arranged horizontally along parts of the physis.
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