Dietary style and acid load in an Italian population of calcium kidney stone formers.

BACKGROUND AND AIMS: Animal protein intake may cause an acid load that predisposes individuals to stones by influencing calcium and citrate excretion. These associations were not confirmed in recent studies. Therefore the present study was aimed to compare acid load of diet in stone formers and controls. METHODS AND RESULTS: Participants to the study were 157 consecutive calcium stone formers and 144 controls. Diet was analyzed in these subjects using a software that evaluated nutrient intake from a three-day food intake diary. This software also estimated the potential renal acid load (PRAL, mEq/day). Twenty-four-hour urine excretion of ions and citrate was measured in stone formers. Stone former diet had lower intake of glucose, fructose, potassium and fiber and higher PRAL in comparison with controls. The multinomial logistic regression analysis showed that stone risk decreased in association with the middle and the highest tertiles of fiber intake and increased in association with the highest tertile of PRAL. The linear multiple regression analysis showed that calcium excretion was associated with the sodium excretion and that citrate excretion was associated with the PRAL and animal protein intake in stone formers. CONCLUSION: Our findings suggest that stone formers may undergo a greater dietary acid load sustained by a low vegetable intake and base provision. Dietary acid load does not appear as the main determinant of calcium excretion, but may promote stone risk by decreasing citrate excretion. Sodium intake may predispose to stones by stimulating calcium excretion.

Calcium sensing receptor and renal mineral ion transport.

Calcium sensing receptor (CaSR) is a component of the C family of the G protein-coupled receptors. It is ubiquitously expressed in human and mammal cells but is more expressed in parathyroid glands and kidney cells. It is located on the cell plasma membrane and senses the changes of extracellular calcium concentrations. Thus, it may modify cell functions according to serum calcium levels. CaSR has a key role in calcium homeostasis because it allows parathyroid glands and kidney to regulate PTH secretion and calcium reabsorption in order to keep serum calcium concentration within the normal range. CaSR appears as an important player in the regulation of renal calcium handling and body calcium metabolism. Thus, CaSR may protect human tissues against calcium excess. In kidneys, its protective effect includes the stimulation of diuresis and phosphate retention, along with the potential prevention of calcium precipitation and deposition in kidney tubules and interstitium.

Neovascularized bone grafts: experimental investigation.

Vascularized bone grafts are standardized procedures in reconstructive surgery but there are some disadvantages: donor site morbidity, limited number of "natural" donor sites, and complex technique. In this study, we test the possibility of creating a "neovascularized" bone graft utilizing a vascular implantation procedure in a rabbit model. Sixteen New Zealand adult white rabbits were used. In each animal, two iliac crest bone grafts (7 x 7 x 10 mm) were harvested. Vascular implantation of the right superficial femoral vessels was performed in one of the two grafts, which was wrapped in a silicone envelope to avoid neovascularization from the surrounding tissues and positioned in a subcutaneous pocket in the right medial thigh. On the left side, the bone block, wrapped in the silicone envelope, was buried subcutaneously without vascular implantation. The operated animals were divided into two groups: Group I included eight rabbits explanted 4 weeks postoperatively and Group II included eight rabbits explanted 8 weeks postoperatively. Tetracycline injection was performed 72 hours preexplantation to evaluate new bone formation. Selective colloidal ink injection in the axial artery was performed to investigate the neovascularization before inclusion in poly-methyl-methacrylate (PMMA). Histological examination was performed in all explanted specimens comparatively. Histological examination 8 weeks after surgery showed a marked neovascularization, with normal bone cells. Tetracycline labeling showed new bone formation with a normal pattern. In all nonvascularized specimens, no viable cells or neovascularization and no bone formation were found. The vascular implantation procedure can induce a good neovascularization with new bone formation in a small bone graft. The possibility of neovascularization induction by the simple vascular implantation procedure has several clinical implications in reconstructive surgery.

The heterodigital reversed flow neurovascular island flap for fingertip injuries.

We report the results of pulp reconstruction with a new heterodigital reverse flow island flap. A dorsolateral flap from the middle phalanx, based on the digital artery is raised from the adjacent uninjured finger. The common digital artery, between the injured finger and the donor finger, is ligated and transected just before its bifurcation. The two converging branches of the digital arteries can be entirely mobilized as a continuous vascular pedicle for the flap. Thus the vascularization is now supplied by reverse flow through the proximal transverse digital palmar arch of the injured finger. To provide sensation the dorsal branch of the proper digital nerve from the donor finger can be included in the flap. Six reverse heterodigital island flaps were used in patients. In five patients the flap was used for pulp reconstruction and in one case for covering a dorsal digital defect. In one case mild venous congestion occurred. Good skin coverage with supple and well-vascularized skin was obtained in each patient. The static two-point discrimination over the flap was between 6 and 15 mm. This new procedure is indicated for extensive pulp defects in fingers in which reconstruction cannot be done using other flaps and as an alternative to microsurgical reconstruction.

Giant cell tumor of the hamate bone.

The authors present two cases of giant cell tumor of the hamate bone. The symptoms and signs were similar in both cases: pain, mild inflammatory changes, and localized swelling. The radiographic picture included lacunar osteolysis with interruption of the cortex in one case, intact cortex but more expansive lysis of the cancellous bone in the other. The findings of greatest interest were constituted by the extreme rareness of the localization, problems related to differential diagnosis, long-term follow-up in one case (20 years) and the different methods of treatment used.

Carpal tunnel syndrome in Madelung's deformity.

The authors describe a case of carpal tunnel syndrome due to Madelung's deformity. They discuss the pathophysiological causes of median nerve entrapment to explain the compression which occurs in this disease and its clinical implications. They take also into consideration the surgical approach to the carpal tunnel in this particular condition.