Transplantation of islet allografts and xenografts in totally pancreatectomized diabetic dogs using the hybrid artificial pancreas.

Previously the authors reported on a Hybrid Artificial Pancreas device that maintained patent vascular anastomoses in normal dogs and, when seeded with allogeneic canine islets, maintained normal fasting blood sugars (FBS) in diabetic pancreatectomized dogs. Eventual failure of these devices was believed to be related to loss of islet viability and/or insufficient islet mass. The current study evaluates the effect of increased islet mass produced by implantation of two islet-seeded devices in pancreatectomized dogs and compares the results with those from dogs that received a single device. Twelve of fifteen dogs receiving single devices showed initial function as determined by elimination or reduction of exogenous insulin requirement; four showed initial function and seven showed extended function (100 to 284 days). Excessive weight loss (more than 20%), despite normal FBS and insulin dependence, required that four animals in this latter group be killed. Devices seeded with xenogeneic islets have met with limited success. One dog that received two bovine islet-seeded devices achieved function for more than 100 days; the remaining bovine-seeded devices (n = 8) functioned for only 3 to 16 days. Porcine islet-seeded devices were assessed by intravenous glucose tolerance tests (IVGTT). Recipients of two devices seeded with allogeneic islets demonstrated improved IVGTT results when compared to those from pancreatectomized dogs and recipients of single devices but were abnormal when compared to intact animals. Histologic examination of device and autopsy material from all failed experiments was performed and showed no mononuclear cell infiltration of the islet chamber or vascular graft material, only a few incidence of device thrombosis, and varying degrees of islet viability as judged by morphologic and immunohistochemical evaluation. The authors believe they have demonstrated progress toward the development and clinical applicability of the Hybrid Artificial Pancreas.

Tumoral calcinosis. Case report with treatment failure.

Periarticular calcifications are the hallmark of a rare entity: tumoral calcinosis. We have followed for 90 months a nine-year-old black girl with involvement of both shoulders. Seven initial local excisions of the mass on the right shoulder were attempted without complete removal and prompt recurrence after each attempt. The entire lesion on the right side, including a cutaneous ulceration, was managed by en masse surgical excision. Preoperative inpatient medical management in the form of low calcium and low phosphorus diet was unsuccessful. Postoperatively, she has remained free of ulceration; however, after two and a half years, the right mass has again increased in size with compression of the brachial plexus. This recurrence occurred despite strict dietary control starting immediately postoperatively. Although there are many advocates of surgical excision of these lesions and, more recently, several cases reported of successful medical management, we find that often a combination approach is necessary to effectively treat tumoral calcinosis and reduce the rate of recurrence.