Parathyroid hormone-related protein (PTHrP) is produced by the pancreatic islet. It also has receptors on islet cells, suggesting that it may serve a paracrine or autocrine role within the islet. We have developed transgenic mice, which overexpress PTHrP in the islet through the use of the rat insulin II promoter (RIP). Glucose homeostasis in these mice is markedly abnormal; RIP-PTHrP mice are hypoglycemic in the postprandial and fasting states and display inappropriate hyperinsulinemia. At the end of a 24-hour fast, blood glucose values are 49 mg/dl in RIP-PTHrP mice, as compared to 77 mg/dl in normal littermates; insulin concentrations at this time are 6.3 and 3.9 ng/ml, respectively. Islet perifusion studies failed to demonstrate abnormalities in insulin secretion. In contrast, quantitative islet histomorphometry demonstrates that the total islet number and total islet mass are 2-fold higher in RIPPTHrP mice than in their normal littermates.PTHrP very likely plays a normal physiologic role within the pancreatic islet. This role is most likely paracrine or autocrine. PTHrP appears to regulate insulin secretion either directly or indirectly, through developmental or growth effects on islet mass. PTHrP may have a role as an agent that enhances islet mass and/or enhances insulin secretion.

In this systematic review, outcomes for total wrist fusion were comparable and possibly better than those for total wrist arthroplasty in rheumatoid patients. In this era of cost-conscious medical care, expensive interventions must demonstrate superior outcomes. Existing data do not support widespread application of total wrist arthroplasty for the rheumatoid arthritis wrist.

Changes in the biomechanics of the lower abdominal musculature as a result of the wide abdominal rectus plication abdominoplasty are discussed in the context of increasing spinal stability, leading to an alleviation of chronic low back pain. An argument is made that this abdominoplasty procedure produces a spine-stabilizing effect by (1) tightening the muscles of the lateral abdominal complex and thus increasing intraabdominal pressure and (2) increasing the efficiency of these muscles so that their effectiveness as spine stabilizers is increased. Even though this is a small series, the fact that all the patients sustained long-term alleviation of their preoperative chronic back pain suggests that the wide abdominal rectus plication abdominoplasty should be considered as an option for patients with weak lower abdominal muscles and intractable low back pain who have failed conservative management.