A modified automated method for isolation of viable pancreatic islets in laboratory animals.

To achieve successful islet transplantation, a high viability is required. For this reason an automated method including two chambers: one for islets isolation and one for recirculation and collection was developed. Recently, we produced a modified version of this work by building a similar system of glass where marbles were not used for disaggregation, and the pancreatic tissue had to be disrupted mechanically before the digestion phase. By using the reconfigured system, we obtained 260 +/- 20 islets from each Wistar albino rat (weighing 220 to 240 g) pancreas. Islets were observed at 35 minutes after the start of perfusion (closed circuit) and the optimum time to stop the isolation determined to be 40 minutes based upon islets viability. Although the present system is configured for islet isolation from small laboratory animals (rat, mouse), we have also obtained thousands of islets at 25 minutes after treatment of a 0.5-g piece of pig pancreas. Compared to the time-consuming manual method usually used for islet isolation from small laboratory animals, the new technique is economic, easy to use, and does not reduce islets viability.

Effect of human somatotropin hormone on cultured rat islets.

Because growth hormone (GH) improves the insulin secretion capacity of isolated human fetal islets in vitro, we sought to show that it positively influences isolated rat islets. Islets isolated from Wistar albino rats by a modified automated system were cultured in media containing 87% RPMI 1640, 10% FCS, 2% antibiotic-antimycotic, and 1% L-glutamine for 12 +/- 2 days. The cultured islets were divided into two groups: growth hormone negative (Group I) and growth hormone positive (Group II). On the 5th day we observed a decrease in the islet cell counts in both groups (Group I 28% versus Group II 45%). On the 10th day, the decrease continued in the GH-negative group (59%), while the count remained stable in the GH-positive group. The viability of rat islets was determined by fluorescein diacetate (FDA) plus propidium iodide (PI) staining. In comparison to the peripheral green, central orange-red staining pattern of Group I islets upon fluorescent microscopy, Group II showed more compact islets. Cultured islets seemed to be brighter than those without GH in the cultured islets. In conclusion, we observed that 2 weeks of incubation in the presence of GH acts positively on cultured rat islets for both their amount and their viability.

Increased basic fibroblast growth factor levels in serum and blister fluid from patients with vitiligo.

Basic fibroblast growth factor (bFGF) is a pleiotropic growth factor which has a high capacity for stimulating normal melanocyte proliferation and suppressing melanogenesis. The close and complicated relationship between bFGF, melanocyte proliferation and melanogenesis raises the theoretical possibility that bFGF may also be involved in the pathomechanism leading to vitiligo. The aim of this study was to compare the serum and suction blister fluid bFGF levels of vitiligo patients (9 females, 11 males) with those of healthy controls (3 females, 8 males). Vitiliginous skin-blister fluid bFGF levels and serum levels were significantly higher in vitiligo patients compared with healthy normal controls. Our data indicate that bFGF might be involved in the pathogenetic chain of events leading to vitiligo. Further studies are needed to define the exact role of bFGF and various other melanocytic mitogens in this disease.