A Verstraeten

Short-term course of 1,25(OH)2D3 stimulates osteoblasts but not osteoclasts in osteoporosis and osteoarthritis

SummaryWe investigated the effect of short-term, 1,25-dihydroxyvitamin D3 therapy (4 μg/day for 4 days) on calcium metabolism in 27 postmenopausal women (11 cases with osteoporosis and 16 cases with osteoarthritis). Bone mass at the axial and appendicular skeleton was higher in osteoarthritis than in osteoporosis. Initial values of calcium metabolism were similar. Osteoporotic and osteoarthritic patients responded with a similar significant increase in serum osteocalcin (+61% and +54%, respectively), fasting urinary calcium excretion (+178% and +124%, respectively) and 24 hour calcium excretion (+148% and +142%, respectively). Parathyroid hormone (PTH) levels decreased significantly in both groups (−30% and −18%, respectively). Osteoclastic bone resorption, evaluated by urinary hydroxyproline excretion, was not stimulated in either group. We conclude that in osteoporosis and also in osteoarthritis (1) 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) stimulation of osteoblast function is similar in production of osteocalcin; (2) the vitamin D target tissues react adequately to 1,25(OH)2D3 stimulation; (3) short-term high dose of 1,25(OH)2D3 does not stimulate bone resorption; and (4) the differences in bone mass between osteoarthritis and osteoporosis are not related to an alteration of the responsiveness to stimulation by 1,25 (OH)2D3.

Prevention and treatment of osteopenia in the ovariectomized rat: Effect of combined therapy with estrogens, 1-alpha vitamin D, and prednisolone

SummaryThe effects of estrogens and 1-alpha were studied in young animals after ovariectomy (OVX) and/or prednisolone (PDN). These medications were given separately or in combination as preventive therapy from the start of the experiment, and as curative therapy starting 3 months later. Changes in bone mass were evaluated by single photon absorptiometry of the femur at the diaphysis (containing mostly cortical bone) and at the distal end of the femur (containing mostly trabecular bone). Radiogrammetry was performed at 50% of the length of the femur. Estrogens prevented further bone loss after OVX and OVX+PDN, given either at the beginning of the experiment or started 3 months later, except for trabecular bone loss immediately after OVX+PDN. After 1-alpha vitamin D, a highly significant increase in BMC and BMD was found in controls, in animals treated with PDN, and after OVX and OVX+PDN. The combination of 1-alpha with estrogens was less effective than 1-alpha but more effective than estrogens alone. After correction for body weight changes globally the same results were found. We conclude that (1) estrogens prevent bone changes after ovariectomy and ovariectomy+prednisolone; and (2) 1-alpha vitamin D highly significantly increased bone mass in male and female rats, and after prednisolone treatment, ovariectomy, and ovariectomy+prednisolone treatment.

Cauda equina syndrome complicating ankylosing spondylitis: Role of computed tomography and magnetic resonance imaging

SummaryWe present two cases of cauda equina syndrome in ankylosing spondylitis. Cauda equina syndrome is a rare complication of ankylosing spondylitis, the pathogenesis of which is not well understood. The onset is insidious with pain and sensory symptoms; sphincter disturbances are common. After a period of increasing neurological symptoms, the condition tends to stabilize. The degree of nerve involvement is variable and can be accurately defined by electromyography. The diagnosis has to be confirmed by computed tomography (CT) or magnetic resonance imaging (MRI); myelography must be avoided. There is no specific treatment, except for pain control.The different clinical presentations and the role of new imaging techniques, CT and MRI, are demonstrated.