Osseous repair with Le Fort I osteotomy.

The effectiveness of rigid and semirigid fixation at various distances between Le Fort I osteotomy segments after different healing periods was evaluated in 16 Macaca fasicularis monkeys. The histologic findings revealed better healing with semirigid fixation.

Parenteral magnesium load testing with 28Mg in weanling and young adult rats.

A sound diagnostic test for Mg deficiency is needed. This is a report of the parenteral Mg load test conducted in weanling and young adult rats fed a purified basal diet containing 3 mg magnesium/100 g with 150 mg of added magnesium/100 g (control) or 0 added magnesium (deficient). Weanlings were studied at about 1 week of dietary treatment and young adults at 2 weeks. The protocol included: a) a 6-hour preload urinary collection; b) an intraperitoneal load of 15 mg of magnesium/kg (weanlings) or 12 mg/kg (young adults) with 2 microCi 28Mg given simultaneously with each load; c) a 6-hour postload urinary collection; d) chemical analysis of selected tissues and urine for Mg; and e) 28Mg counting 6 and 24 hours postload. Controls all excreted large amounts of Mg pre- and postload, retaining less than 26% of nonradioactive loads. They had high urinary 28Mg counts. In Mg-deficient animals, the concentration of Mg in bone more than halved. These animals avidly conserved Mg and retained over 85% of nonradioactive Mg loads. Their 28Mg activity in vital organs was 3--6 times greater than in controls. We concluded that the parenteral Mg load test reliably identifies severe Mg deficiency.

Necrotizing sialometaplasia in a patient with Buerger's disease and Raynaud's phenomenon.

This report describes a case of necrotizing sialometaplasia (NS) in a patient diagnosed as having Buerger's disease with secondary Raynaud's phenomenon. The danger of misdiagnosing NS as a malignant lesion is emphasized. Possible causal relationships between the patient's medical condition and the lesion are discussed.

The effects of zinc on ectopic bone formation.

The effect of dietary zinc deficiency was studies in ectopic bone formation subsequent to Achilles tenotomy and also following the implantation of demineralized bone matrix in the muscle of rats. Three experiments were performed. The first was designed to investigate the relationship between zinc and calcium concentration during the formation of ectopic bone in rats fed a commercial laboratory ration, the second concerned the effects of dietary zinc deficiency on ectopic bone formation, and the third studies the subsequent effects of dietary zinc repletion on ectopic bone formation. The results indicated that, with the commercial ration, zinc increased concomitantly with calcium during ectopic bone formation in rats. Dietary zinc deficiency caused a retardation of ectopic bone formation and a significant reduction of in situ zinc and calcium concentration. Dietary zinc repletion to zinc-deficient animals restored the zinc concentration in ectopic bone to a level comparable to that of zinc-sufficient animals. Thus, these experiments present strong evidence that zinc plays an active role in bone metabolism.