Biomedical subjects

Francisco Forriol

Publications and source records attributed to Francisco Forriol.

10 recordsLinked to original sources

PubMed2006

Gene expression and proliferation analysis in young, aged, and osteoarthritic sheep chondrocytes effect of growth factor treatment.

Cartilage is a support tissue with a poor capacity to self-repair. Its cells, chondrocytes, are responsible for synthesizing and renewing the matrix that surrounds them in a constant turnover mechanism. Autologous chondrocyte implantation (ACI) is one of the techniques that promises to be an alternative to common strategies for chondral lesions. To apply this technique, a large amount of cells must be obtained. In our work, we studied the state of cells from different cartilage (young, aged, and osteoarthritic sheep) cultured in monolayer by analyzing their proliferation rate using bromodeoxyuridine and their gene expression profile by RT-PCR. A decrease was found in expression of type II collagen and aggrecan in aged, osteoarthritic, and passaged chondrocytes. Treatment of cells with growth factors aFGF, IGF-I, TGF-beta, and OP-1 improved the proliferation rate in all cells studied and stimulated gene expression of type II collagen, aggrecan, and TGF-beta. Osteoarthritic cells showed a poor response according to matrix gene expression, while young cells responded properly, and aged chondrocytes showed a moderate response. These results suggest that the state of cartilage may affect the behavior of cultured chondrocytes.

Aggrecans↗

PubMed2005

Morphologic comparison of cervical, thoracic, lumbar intervertebral discs of cynomolgus monkey (Macaca fascicularis).

The aim was to analyze the morphological differences of the intervertebral disc and endplates at different levels. Forty-five vertebral motion segments were obtained from the spine of nine 3 to 4-year-old cynomolgus monkeys (Macaca fascicularis). From every spine, five discs were sectioned (C5-C6, T3-T4, T9-T10, L2-L3, L4-L5). In all the groups, tissue samples were collected and sections were stained with Masson's trichrome, Safranine-O and van Gieson's connective tissue stain to analyze the intervertebral discs. Immunohistochemistry was performed, using specific antibodies to detect collagens I and II. The intervertebral disc height, the maximum nucleus pulposus height, the superior and inferior endplate heights were histomorphometrically measured and different indexes were calculated to compare the differences between specimens of the same animal and between discs of the same level, and finally the differences between groups of discs of different levels. There were no differences existing in annular fibers anchoring on the endplate between discs of different levels. A positive immune reaction for type I collagen was observed in the longitudinal ligaments and in the annular region adjacent to them. Collagen II immune reactivity was found in the annulus close to the nucleus pulposus, in the endplates and in the nucleus. There were no differences between discs of different levels in the collagen I and II localization. The height of the discs varied along the spine. The smallest value was measured in T3-T4, with a larger increase caudally than cranially. The highest value was measured in L2-L3. A cervical disc was 55% the height of a lumbar one. The endplate height increased along the length of the spine. The inferior EP was always higher than the superior. The study provides a detailed structural characterization of the intervertebral disc and may be useful for further investigations on the disc degeneration process.

Animals↗

PubMed2005

Bone development: interaction of molecular components and biophysical forces.

A deeper understanding of skeletal development comes from knowledge of the molecular components, cell and tissue structure, and biophysical and vascular mechanisms underlying physiologic function. Endochondral and intramembranous bone formation mechanisms are active during long bone synthesis. Most endochondral growth in length occurs at the physes by the coordinated actions of cell proliferation, matrix synthesis, and chondrocyte hypertrophy. Several intrinsic molecules act to modulate physeal structure and function whereas extrinsic molecules, such as hormones, provide systemic regulation of growth. Biophysical forces develop intrinsically within the growing bone, serving to enlarge it in three dimensions, while extrinsic forces resist and channel expansion into normal recognizable and functional forms. Newer imaging modalities, such as magnetic resonance imaging, are highly effective in assessing epiphyseal vascularity and differentiating fibrous, cartilaginous, mineralized and osseous tissues in prenatal and postnatal developing bone. This study illustrates the interplay between the molecular and biophysical aspects of normal bone growth, shows ways in which altered development leads to abnormal structures, and provides examples where biologic and biophysical interventions can affect bone development in favorable ways.

Biomechanical Phenomena↗

PubMed2004

Radiological and histological analysis of cortical allografts: an experimental study in sheep femora.

INTRODUCTION: We developed an experimental model in sheep femora to evaluate the process of cortical allograft incorporation. MATERIALS AND METHODS: Twenty-four sheep were divided into four groups according to the various treatments of cortical allografts as follows: fresh, frozen, autoclaved, and frozen with perforation. Periodical radiographic and histological evaluations were performed for each group. RESULTS: Perforated frozen allograft proved to be superior radiographically in the first stage to fresh, frozen, and autoclaved forms. Revascularization was demonstrated by both Spalteholz's technique and histological examination. Histological analysis also showed creeping substitution, from the host bone to the allograft, which increased the reabsorption to facilitate new bone penetration, including endochondral ossification at the host-graft interface. CONCLUSION: We believe that endochondral ossification is probably a biological event occurring routinely during the bone healing process and that the processes of incorporation of variously treated cortical allografts differ only at the early phase of implantation.

Animals↗

PubMed2004

Nonunion: general principles and experimental data.

Nonunions of long bone fractures can be treated successfully with one operative procedure in more than 90% of patients. In fact, 80% of patients can have good to excellent final restoration of mechanical axis alignment and proper length. Patients with infected nonunions may require more than one procedure to eliminate infection and heal the nonunion. Treatment must be tailored to the individual patient to address all components of the problem. We reviewed the main experimental data regarding the knowledge of nonunions and the basic methods that may be applied to the treatment of nonunions.

Animals↗

PubMed2003

Articular cartilage degeneration after frozen meniscus and Achilles tendon allograft transplantation: experimental study in sheep.

PURPOSE: The purpose of this study was to analyze cartilage degeneration in knees after total medial meniscectomy, transplantation of fresh-frozen meniscus allograft, and Achilles tendon allograft. TYPE OF STUDY: Experimental study. METHODS: We have studied the articular cartilage in the medial compartment of the left knees in 32 sheep aged 5 to 6 months, with 8 animals in each group. The study was performed after meniscectomy (group I), transplantation of fresh-frozen meniscus allograft (group II), use of fresh-frozen Achilles tendon allograft (group III), and in a control group (group IV). For the histologic study, all samples were stained with Masson's trichrome and Safranine-O. Mankin's score was applied to grade the histologic damage to the articular cartilage. RESULTS: The group with the greatest number of degenerative changes was group III, followed by groups I and II. The percentage of thickness of cartilage detected by Safranine-O stain was found to be significantly different in both tibia and femur between the control group and the other 3 groups, but not among groups I, II, and III. The immunoreactivity of the articular surfaces in tibia and femur showed notable differences in all the groups. Collagen X was present in the degenerative hypertrophic chondrocytes in the damaged articular surfaces. CONCLUSIONS: Meniscal replacement with meniscal and Achilles tendon allografts provides partial protection against articular damage after a meniscectomy.

Achilles Tendon↗

PubMed2003

The development in footprint morphology in 1851 Congolese children from urban and rural areas, and the relationship between this and wearing shoes.

The footprints of 1851 Congolese children were studied using the index of Chippaux-Smirak, Staheli's index of the arch, and Clarke's angle. The sample consisted of 906 girls and 945 boys aged between 3 and 12 years, including city children who wore shoes and children from rural areas who had gone barefoot. At the ages of 3 and 4 years, most feet were morphologically flat, but the proportion of flat feet decreased with age in both sexes. Boys had a greater tendency for flat feet. According to the three parameters studied there was a greater proportion of flat feet in the urban environment. By multiple regression analysis the three parameters we had studied identified age as the primary predictive factor for flat feet. As in previous studies in western populations, the girls had a higher inner arch than the boys and footwear had very little influence on the morphology of the foot.

Child↗

PubMed2002

Effects of preservation on the mechanical strength and chemical composition of cortical bone: an experimental study in sheep femora.

Preservation methods have enabled bone banks to furnish cortical bone grafts to orthopaedic surgeons. However, cortical bone preserved by freezing and autoclaving, may be weakened by these treatments. To test this hypothesis we compared the ultimate tensile strength of freshly harvested sheep femora with that of femora which were frozen at -20 degrees C for 60 days, or autoclaved at 134 degrees C for 8 min. We measured the collagen and mineral contents (calcium, phosphorus, magnesium) and hydroxyproline of the specimens and tested for changes induced by preservation. Mechanical three point tests showed that frozen femora were significantly stronger than either fresh or autoclaved femora (p<0.05). Frozen specimens also had the highest phosphorus level, indicating these measures are related to strength. Cortical bone is not significantly weakened by autoclaving or freezing. This result does not imply that preserved grafts are clinically interchangeable with fresh grafts, rather, it suggests that future studies should focus on post surgical issues, such as the rate of remodeling and integration, which may be sensitive to preservation technique.

Animals↗

PubMed2002

Knee immobilization on meniscal healing after suture: an experimental study in sheep.

Immobilization and nonweightbearing may influence the healing of sutured meniscal lesions in the avascular zone. In 12 sheep, 3 to 4 months of age, a 0.5-cm longitudinal lesion was made in the middle segment and posterior portion of the medial meniscus of the left knee in the avascular zone. The lesion was sutured immediately. The knees of six sheep were immobilized with a monolateral external fixator, which crossed the knee, and the knees in the other six sheep were not immobilized. The animals were sacrificed 6 weeks after the operation. Specimens from the anterior meniscus were used for histologic and vascular studies, and the posterior meniscus was used for mechanical testing. Repair was observed in two of 12 sheep in the form of fibrous tissue. Fibrochondrocytes and synovial cells were involved. Meniscal fibrochondrocytes from the nearest meniscal tissue, synovial cells from the femoral and tibial meniscal surfaces, and fibroblastic cells migrating through the suture channel provide cell access to the meniscus lesion. Sutured menisci, immobilized or not, support less than 50% of a normal load and are mechanically weak.

Animals↗

PubMedDate not supplied

Influence of the type of load on the cervical spine: a study on Congolese bearers.

BACKGROUND CONTEXT: Cervical spine suffers degenerative changes with age and activity. PURPOSE: The aim is to study the cervical spine of African head bearers by analyzing clinical changes and radiographic degenerative signs in comparison with a control group. STUDY DESIGN: Two groups of bearers, 28 bearers of heavy loads (50 to 60 kg) over short stretches and 33 bearers who carried bundles or lighter loads (30 to 35 kg) over long distances were clinically and radiographically examined and compared with a control group of 36 building industry workers who did not bear weights on their heads. METHODS: We noted the age, height, weight, body mass index (BMI), weight of load, years they had been working, width and length of the neck and any painful symptoms. We carried out a functional exploration of the cervical spine and a lateral radiograph of the cervical spine to assess degenerative changes and quantified the degenerative changes in the vertebral bodies and the discs. The angle of lordosis was measured. RESULTS: We found more prolapsed discs (p < .01) in the heavy-load bearing group than in the control group. The heavy-load bearers had larger neck width (p < .01) and more disc herniations (p < .05) than the bundler bearers. The frequency of prolapsed discs was higher at C5-C6 and C6-C7 levels. The listhesis was more frequent among bundle bearers than in heavy-load bearers and control group. A correlation between the number of disc herniations and age (p < .01) and years of work (p < .05) was observed. When all the bearers were compared with the control group, the differences found were the number of prolapsed discs, stiffness in the neck and reported pain (p < .01). CONCLUSION: Load bearing on the head, particularly bearers of heavy loads, produced more radiographic degenerative signs, much stiffness in the neck and more reported pain than the control group.

Adult↗