Biomedical subjects

F Santolini

Publications and source records attributed to F Santolini.

4 recordsLinked to original sources

PubMed1996

Integrin synthesis and utilization in cultured human osteoblasts.

This study describes the adhesion of human osteoblasts, cultured in vitro, to proteins of the extracellular matrix, the biosynthesis of integrins, their topography and organization in focal contacts. The adhesion of osteoblasts to laminin, type I collagen, vitronectin and fibronectin was 77-100%, in 2 h and at 55 nM substrata concentration, and it was accompanied by spreading of the cells. Adhesion to fibronectin (FN), laminin (LN) and type I collagen (COL) was inhibited by antibodies to the beta 1 integrin and antibodies to the alpha 5 chain affected adhesion only to fibronectin. Using a panel of polyclonal antibodies against alpha 2, alpha 3, alpha 5, alpha v, beta 1 and beta 3 integrins we detected synthesis of alpha 3 beta 1, alpha 5 beta 1, alpha v beta 3, and an alpha v beta 1-like dimer by immunoprecipitation of metabolically labelled cell lysates. Studies of immunolocalization demonstrated the presence of the same integrins identified in lysates, plus alpha 4, alpha 1 and beta 5 subunits. In cells adhering in the presence of serum we showed organization of beta 3 and alpha v integrins in focal contacts. In cells adhering to fibronectin alpha 5 and beta 1 integrins were localized in focal contacts. In cells spread on laminin or type I collagen none of the integrins investigated was localized in focal contacts.

Adult↗

PubMed1993

Differential expression of alkaline phosphatase in clones of human osteoblast-like cells.

We established cultures of cells growing out from adult bone chips and maintained them through 12 passages in culture. The cultures showed osteoblastic phenotype accompanied by synthesis of collagen type I, osteonectin, alkaline phosphatase, and osteocalcin. We report the characterization of 21 clones obtained from three different individual primary cultures. We studied the expression of osteonectin, alkaline phosphatase, collagen, and osteocalcin in the clones. Metabolic labeling showed production of type I collagen and of osteonectin in all clones studied. In two-thirds of the clones and in mass cultures alkaline phosphatase was not detected at passage 2, but it was detected in increasing amounts at later passages in culture. The clones attained different but detectable levels of expression of this marker by passage 8. The different levels in the expression of alkaline phosphatase in positive clones may be because they were derived from cells at different stages of osteoblastic maturation or due to small changes in microenvironment. The alkaline phosphatase-positive clones were tested for osteocalcin, and they showed measurable expression only at passage 10. A third of the clones obtained were negative for alkaline phosphatase during 12 passages in culture. The obtainment of clones unable to produce alkaline phosphatase may be due to loss of differentiating potential under the in vitro culture conditions. The growth rate and potential of all clones studied were similar through 12 passages in culture, regardless of their potential for expression of alkaline phosphatase.

Adult↗

PubMed1993

The closed treatment of severe malleolar fractures.

The authors studied, with clinical and radiological criteria the results of closed treatment (reduction by manipulation and immobilization in a plaster cast for 7 or 8 weeks) of severe displaced malleolar fractures. Of 145 patients who had suffered an ankle fracture and were treated with closed methods between 1979 and 1989, 78 were reviewed, with an average follow-up of 6.2 years. The main difficulties of closed treatment concerned reduction of the fractures; anatomical reduction was achieved only in 32.4% of the cases, and deterioration of the position achieved often occurred (26.2%). Although some joints healed in a fair position, subjective and objective late results were excellent or good in 77% of the cases, fair in 20.5% and poor in 2.6%. The most common clinical outcome was a slight decrease of the range of motion in the injured ankle, which was found in 68% of the cases. Arthritis developed in 28.2% of the reviewed ankles, both after an initial good reduction as well as after an initial poor reduction. A complete failure of closed treatment occurred in 8.3% of the cases, caused by an interpositioning of soft tissues among bone fragments leading to unsuccessful manipulation or by late deterioration of the initial position of reduction causing healing of the fracture in a poor position (severe talar shift).

Adolescent↗

PubMedDate not supplied

Considerations on seven cases of breakage of the polyethylene acetabular cup.

The authors describe seven cases of breakage of the polyethylene acetabular cup observed in 6 patients (5 females and 1 male) after a period of time ranging from 2 to 11 years postsurgery. By comparing the results obtained with those reported in the literature the authors analyze the possible etiopathogenesis of this rare late complication in total hip arthroplasty, which they particularly believe to be caused by hyperwear and fatigue phenomena of the acetabular cup, in turn caused by mechanical overloading.

Acetabulum↗