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Over the past several years, there has been an increasing interest in the biology of bone repair and potential technologies for enhancing fracture-healing. Part of this interest is derived from the growing age of the population and the recognition that increased age carries an increased risk of complications after fracture. Although use of locally implanted or injected growth factors has received the most attention, systemic treatments for the enhancement of bone repair, especially for situations in which bone repair may be diminished or delayed, are now under investigation. Since the approval of parathyroid hormone (PTH) as an anabolic treatment for osteoporosis, there has been an increasing interest in other potential clinical uses for this compound in musculoskeletal conditions. It is now widely recognized that PTH administration is an effective therapy to increase bone mineral density and prevent fractures in patients with osteoporosis. More recently, a growing body of evidence has supported the conclusion that PTH will also be an effective anabolic therapy for the enhancement of bone repair after fracture. This review focuses on the recent research demonstrating the potential of PTH in the management of bone repair in a number of fracture models and also highlights the ongoing studies into the mechanisms of PTH actions on endochondral bone repair. [ABSTRACT FROM AUTHOR]

Rationale: Treatment of latent tuberculosis (TB) infection with weekly rifapentine and isoniazid is a potentially effective alternative to current therapies.Objectives: To compare the efficacy of weekly rifapentine/isoniazid to daily rifampin/pyrazinamide in preventing TB in household contacts of patients with pulmonary TB in Brazil.Methods: Contacts of patients with TB were randomized to rifapentine 900 mg/isoniazid 900 mg once weekly for 12 wk or rifampin 450-600 mg/pyrazinamide 750-1,500 mg daily for 8 wk and followed for at least 2 yr.Measurements: TB rates, adverse events, and adherence to therapy.Main Results: A total of 399 household contacts were enrolled, 206 in the rifapentine/isoniazid arm and 193 in the rifampin/pyrazinamide arm. The median age was 34 yr, median weight was 63 kg, 60% of participants were female, and only one patient was HIV infected. Rifapentine/isoniazid was well tolerated, but the trial was halted by the investigators before completion because of unanticipated hepatotoxicity in the rifampin/pyrazinamide arm. Twenty of 193 participants (10%) receiving rifampin/pyrazinamide experienced grade 3 or 4 hepatotoxicity, compared with 2 of 206 participants (1%) on rifapentine/isoniazid (p<0.001). There were no hospitalizations or deaths due to hepatotoxicity, and all participants' liver enzyme levels returned to normal during follow-up. During follow-up, four cases of active TB developed, three in the rifapentine/isoniazid group and one in the rifampin/pyrazinamide group (1.46 vs. 0.52%; difference, 0.94%; 95% confidence interval, -1.6 to 3.7%).Conclusions: Rifapentine/isoniazid was better tolerated than rifampin/pyrazinamide and was associated with good protection against TB. Rifapentine/isoniazid weekly for 12 wk is likely a promising therapy for latent TB infection. [ABSTRACT FROM AUTHOR]