Juvenile osteoporosis: recognizing the risk.

Osteoporosis in children is often an undiagnosed condition. Diagnosis is usually made after several fractures occur with minimal trauma or radiographs demonstrate hypodense bones. The relationship of bone mineral density (BMD) to fracture risk in children is controversial.

Characterization of interferon gamma receptors on osteoclasts: effect of interferon gamma on osteoclastic superoxide generation.

Osteoclasts are the primary cells responsible for bone resorption. Osteoclast formation and bone resorption activities involve processes tightly controlled by a network of cytokines. The presence of interferon gamma (IFN-gamma) receptors on osteoclasts is a necessary prerequisite for IFN-gamma to directly affect osteoclastic activity.

A new superoxide-generating oxidase in murine osteoclasts.

Superoxide production contributes to osteoclastic bone resorption. Evidence strongly indicates that NADPH oxidase is an enzyme system responsible for superoxide generation in osteoclasts. A membrane-bound subunit, p91, is the catalytic domain of NADPH oxidase.

IFN-gamma enhances osteoclast generation in cultures of peripheral blood from osteopetrotic patients and normalizes superoxide production.

Interferon-gamma (IFN-gamma) treatment increases osteoclastic bone resorption in vivo in patients with malignant osteopetrosis (OP). The treatment effect was studied in vitro in osteoclasts generated by culturing peripheral white blood cells (PWBC) from OP patients and normal human control subjects. Osteoclasts were treated with or without IFN-gamma prior to the end of the culture period.

Cytophilic immunoglobulin G binding on neutrophils from a child with malignant osteopetrosis who developed fatal acute respiratory distress mimicking transfusion-related acute lung injury.

A 16-month-old boy, diagnosed at age 3 months with osteopetrosis, was treated since age 6 months with rhIFN-gamma in combination with rhM-CSF. The child developed acute respiratory distress within 1 hr of a paternal platelet transfusion. Both the child and the father were blood group type O, and platelets were collected the previous day from the father.