Reconstruction of parasacral hernia with acellular human dermis graft.

Parasacral hernias are defects through the pelvic floor which occur as the result of sacral resection. These defects are often large, and are frequently the result of treatment for sacral malignancies. This report documents the case of a 71-year-old woman who underwent radical coccygectomy and partial sacrectomy for a chordoma and subsequently presented 1 year later with a large parasacral hernia. The defect was repaired using an acellular human dermis graft with a gluteus maximus muscle-advancement flap overlay. This article summarizes the current literature of this challenging clinical problem, and examines the use of acellular human dermis in the repair of complex hernias.

Chloride/phosphate ratio in primary hyperparathyroidism.

The chloride/phosphate (Cl:PO4) ratio is known to help distinguish between the hypercalcemia of primary hyperparathyroidism (HPT) and hypercalcemia from other causes. The Cl:PO4 ratio of 106 patients with surgically proven primary HPT was compared with that of 126 normocalcemic healthy outpatients to examine its usefulness as a confirmatory test for primary HPT. The Cl:PO4 ratio was significantly higher in patients with HPT (42.5 +/- 7.0) compared with healthy controls (28.7 +/- 4.6). Patients with HPT and mild renal insufficiency (serum creatinine, 1.5-2.4 mg/dL) also showed a significant increase in the Cl:PO4 ratio (37.3 +/- 6.6) as did those with HPT with borderline elevations in serum calcium (calcium < 11; Cl:PO4, 40.3 +/- 5.6). A Cl:PO4 ratio > or = 33 is a reliable diagnostic test for primary HPT when compared with a normal population. The Cl:PO4 ratio is also of value in the evaluation of the patient with suspected HPT and borderline calcium elevation and those with mild renal impairment. These data suggest that an inexpensive Cl:PO4 ratio might replace serum parathormone assay as a confirmatory test in the evaluation of suspected primary HPT, especially for those patients in whom a localizing study (sestamibi scan) is obtained before neck exploration.

Design and construction of a uniaxial cell stretcher.

In vitro mechanical cell stimulators are used for the study of the effect of mechanical stimulation on anchorage-dependent cells. We developed a new mechanical cell stimulator, which uses stepper motor technology and computer control to achieve a high degree of accuracy and repeatability. This device also uses high-performance plastic components that have been shown to be noncytotoxic, dimensionally stable, and resistant to chemical degradation from common culture laboratory chemicals. We show that treatment with glow discharge for 25 s at 20 mA is sufficient to modify the surface of the rubber to allow proper adhesion for polymerization of aligned collagen. We show through finite element analysis that the middle area of the membrane, away from the clamped ends, is predictable, homogeneous, and has negligible shear strain. To test the efficacy of the mechanical stretch, we examined the effect of mechanical stimulation on the production of beta(1)-integrin by neonatal rat cardiac fibroblasts. Mechanical stimulation was tested in the range of 0-12% stretch and 0-10-cycles/min stretch frequency. The fibroblasts respond with an increase in beta(1)-integrin at 3% stretch and a decrease at 6 and 12% stretch. Stretch frequency was found to not significantly effect the concentration of beta(1)-integrin. These studies yield a new and improved mechanical cell stimulator and demonstrate that mechanical stimulation has an effect on the expression of beta(1)-integrin.