Pregnancy and lactation induce dynamic changes in maternal bone and calcium metabolism. A novel cytokine termed osteoprotegerin (OPG)/osteoclastogenesisinhibitory factor (OCIF) was recently isolated; this cytokine inhibits osteoclast maturation. To define the effects of pregnancy and lactation on circulating OPG/OCIF in mothers, we studied the changes in the levels of OPG/ OCIF as well as those of calcium-regulating hormones and biochemical markers of bone turnover in the maternal circulation during pregnancy (at 8-11 weeks, at 22-30 weeks, at 35-36 weeks and immediately before delivery) and lactation (at 4 days and at 1 month postpartum).Serum intact parathyroid hormone levels did not change and were almost within the normal range in this period. In contrast, serum 1,25-dihydroxyvitamin D levels increased with gestational age and were above the normal range during pregnancy. After delivery, they fell rapidly and significantly (P<0·01) to the normal range. The levels of serum bone-specific alkaline phosphatase, one of the markers of bone formation, increased with gestational age.After delivery, these levels were further increased at 1 month postpartum. The levels at 1 month postpartum were significantly higher than those at 8-11 and 22-30 weeks of pregnancy (P<0·01 and P<0·05 respectively). The levels of serum C-terminal telopeptides of type I collagen, one of the markers of bone resorption, did not change during pregnancy. After delivery, they rapidly and significantly (P<0·01) rose at 4 days postpartum, and had then fallen by 1 month postpartum. Circulating OPG/ OCIF levels gradually increased with gestational age and significantly (P<0·01) increased immediately before delivery to 1·40 0·53 ng/ml (means S.D.) compared with those in the non-pregnant, non-lactating controls (0·58 0·11 ng/ml). After delivery, they fell rapidly to 0·87 0·27 ng/ml at 4 days postpartum and had fallen further by 1 month postpartum.These results suggest that the fall in OPG/OCIF levels may be partially connected with the marked acceleration of bone resorption after delivery.

To determine which clinical factors are useful for predicting concomitant injuries of the cervical spine and cervical spinal cord in persons with head injuries, we examined the nature and mechanisms of cervical injuries. For 109 forensic autopsies of persons with head injuries, the cause of injury, mechanism of cervical injury, survival time, and anatomic injury severity (1990 revision of the abbreviated injury scale [AIS] and injury severity score) were determined. Traffic accidents were the most common cause of injuries (41.3%), followed by slips and falls (24.8%), assaults (17.4%), and falls from height (9.2%). The mean maximum AIS scores and the AIS scores of the head or neck were similar in the 4 groups. Cervical spine injuries and epidural or subdural hemorrhages of the cervical spinal cord were more common in persons dying in traffic accidents and falls from height than in persons dying in slips and falls or assaults. Cervical injuries were significantly more common in persons sustaining frontal impacts than lateral or rear impacts. The most common cervical hyperextension injuries were atlanto-occipital and atlantoaxial dislocation and injuries of the 5th intervertebral disc. Our results suggest that persons with injuries of the head due to high-energy frontal impacts should be carefully examined for concomitant cervical injuries. These findings should be helpful for decreasing preventable deaths from undiagnosed cervical injuries in head-injured persons.

No abstract