Biomedical subjects
Publications and source records attributed to G Santacroce.
Interactions between cells from human giant cell tumors of bone and the extracellular matrix protein laminin were studied. Cells were capable of recognizing this substratum via a RGD-independent mechanism. Recognition induces adhesion and spreading onto laminin. This protein triggered the release of cellular FN which in turn enhanced recruitment of the beta 1 chain-containing integrin receptor.
The hyperglycemic effect of 28 g sucrose, taken during a mixed meal, was studied in six insulin-dependent diabetes mellitus (IDDM) patients controlled by artificial pancreas. On 2 consecutive days the patients were given, in random order, two Italian meals containing macaroni, bread, meat, vegetables, fruit, olive oil, and an eggnog made with sucrose (meal A) or saccharin (meal B). The two meals were isocaloric and contained equal amounts of carbohydrates. The feedback control on blood glucose continued for 180 min after the meals. Plasma glucose levels and insulin infusion rates delivered by the artificial pancreas after the two test meals did not show any significant differences regarding basal and peak values, peak times, and areas under the curves. A modest amount of sucrose, taken during a mixed meal, does not produce a hyperglycemic effect higher than an equal amount of complex carbohydrates in IDDM patients controlled by artificial pancreas. The same may be expected in well-controlled IDDM patients in conventional therapy because a correlation exists between insulin requirement for conventional therapy and insulin delivered during glucose-controlled insulin infusion.
Osteoclast resorb bone in an acid compartment formed by the bone-attachment site. The low pH of the resorption compartment provides a lysosome-like milieu suitable for acid proteases to degrade collagen. Solubilization of the hydroxyapatite that makes up bone mineral consumes about 2 moles of protons per moles of calcium dissolved, requiring a massive proton flux to maintain a low pH in the resorption compartment. In order to determine how the osteoclast maintains a physiological cytoplasmic pH while secreting massive amounts of acid, we studied the intracellular pH of osteoclasts using esterified fluorescein derivatives while controlling the electrolyte composition of the medium. The principal finding is that osteoclasts have a high capacity for chloride/bicarbonate exchange which enables them to maintain normal intracellular pH in the face of a large loading of base equivalents. Thus, the overall process of proton secretion during bone resorption is similar to the polarized acid elimination by renal epithelia, involving a proton pump on one surface of the cell, and a Cl-/HCO3- exchange to maintain cytoplasmic pH.
In this study the effect of high extracellular calcium concentration has been evaluated, by immunofluorescence, on podosome expression in chicken osteoclasts. Cells were cultured in presence of 0.2 and 4 mM calcium for 90 minutes and microfilaments were detected, after fixation and permeabilization, by decoration with rodhamine conjugated phalloidin. Results showed that increased extracellular calcium concentration induces the inhibition of podosome expression indicating that these close-contact areas are capable of calcium-mediated regulation.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The aim of the study was to investigate the effects of regularly eating a moderate amount of sucrose (30 g/day) in 12 type 1 (insulin-dependent, IDDM) diabetic outpatients in fair blood glucose and lipid control. Two diets, each lasting two months, were compared in a randomized cross-over study. The former was a high-carbohydrate high-fiber diet for diabetic patients with Italian alimentary habits, the latter had the same composition except that 30 g of sucrose replaced 30 g of complex carbohydrates with high glycemic index (bread). The two diets contained equal amounts of carbohydrates, proteins and lipids; the only difference being the contribution of oligosaccharides to total carbohydrates (22% vs 34%) and cholesterol amount. During the control diet, glycosylated hemoglobin was substantially unchanged in both control and sucrose diet periods (control diet: 6.91 +/- 0.29 (SE) vs 6.80 +/- 0.25%; sucrose diet: 6.75 +/- 0.31 vs 6.91 +/- 0.36%). This was true also for fructosamine (control diet: 3.92 +/- 0.21 vs 3.76 +/- 0.18%; sucrose 3.50 +/- 0.14 vs 3.64 +/- 0.20 mmol/l). Circulating blood lipid levels, body weight and daily insulin dose did not show any significant variations during the study. Moderate amounts of sucrose may be allowed to IDDM patients with Italian alimentary habits without worsening diabetic control.
Explore the source record for details and available documents.
The effects of mixing short- and intermediate-acting insulins (Actrapid MC and Monotard MC) were studied in seven diabetic patients. On different days, 0.16 IU/kg of Actrapid and 0.24 IU/kg of Monotard were administered to each subject in separate injections and combined in the same syringe. Free-insulin curves and the biologic effect of insulin, assessed by the glucose-clamp technique, were compared. The absorption rate of regular insulin was higher when injected separately from the intermediate-acting preparation: the incremental areas of free insulin above basal levels, up to 90 min after the administration of the hormone, were 32 +/- 5 vs. 21 +/- 3 microU X ml-1 X min-1 (P less than .02). In the same period, glucose infused to sustain glycemia showed no significant differences (2.8 +/- 0.4 vs. 2.4 +/- 0.3 mg X kg-1 X min-1 after the administration of insulin in separate and combined injection, respectively). The difference in insulin profiles is not translated into a significant difference in glucose requirement. This might be a consequence of a flattening of the insulin dose-response curve due to insulin resistance of diabetic subjects. The slight delay in insulin action of Actrapid when mixed with Monotard is probably irrelevant in clinical practice.
Severe resistance to subcutaneous insulin with normal sensitivity to intravenous insulin developed in a 39 year old woman affected by type 1 diabetes mellitus. The patient had been treated for ten months with continuous intravenous or intraperitoneal insulin before undergoing pancreatic transplantation. After surgery repeated plasmapheresis were performed and immunosuppressive therapy was undertaken. When studied again, one month after surgery, the patient showed normal sensitivity to subcutaneous insulin. Our data suggest that plasmapheresis and/or immunosuppressive treatment could have played a role in reversing insulin resistance.