Effect of cholecalciferol supplementation on blood glucose in an experimental model of type 2 diabetes mellitus in spontaneously hypertensive rats and Wistar rats

BACKGROUND: Vitamin D might have an influence on glucose concentrations, due to the presence of VDR receptors on the pancreas. We established an experimental model of type 2 diabetes in spontaneously hypertensive rats (SHR) and Wistar rats in order to investigate the glycemic response. METHODS: SHR males (n=6) and Wistar rats (n=6) weighing approximately 89+/-5.5 g and 123.5+/-6.5 g, respectively, after 7 days of basal period, had the chow pattern substituted (350 kcal/100 g) for a hypercaloric/hyperlipidic (HC/HL) diet (490 kcal/100g) and then injected with 40 mg/kg (SHR) and 20 mg/kg (Wistar) streptozotocin I.P. After the creation of diabetes, the rats suffered daily gavage of cholecalciferol (12.5 microg/kg(-) (1)) for 14 days. The blood glucose was assessed twice a week with a glucometer. The data were analyzed by ANOVA. RESULTS: SHR and Wistar rats fed on a HC/HL diet gained 60 g and 32 g in once week, vs. the basal period, where they only gained 23 g and 13 g, respectively. The cholecalciferol supplementation did not change the glucose concentration in all of the SHR animals. About 40% of the group responded by treatment with reduction of about 60% in glucose concentrations. We did find a 40% of the blood glucose levels in all Wistar rats. CONCLUSIONS: Cholecalciferol is able to reduce blood glucose in this experimental diabetes model.     

1H-NMR detectable fatty acyl chain unsaturation in excised leiomyosarcoma correlate with grade and mitotic activity.

We report on the use of 1H-NMR two-dimensional total correlated spectroscopy (2D TOCSY) at 600 MHz for an ex vivo analysis of fatty acyl chain lipid in normal smooth muscle and a series of primary retroperitoneal leiomyosarcomas. These TOCSY spectra were used to identify and quantitate the methylene protons situated between unsaturated site protons (D) to those bordered by only one unsaturated site proton (C). The D/C cross-peak volume ratios determined for oleic (18:1), linoleic (18:2), linolenic (18:3), and arachidonic (20:4) acids were 0.0, 1.3, 2.7, and 4.0, respectively, suggesting that this ratio can be a measure of the degree of unsaturation for fatty acyl chains of lipids. The D/C cross-peak volume ratio was found to be proportional to the mean mitotic activity (r = 0.94) in nine smooth muscle tissues. These results suggest, that for leiomyosarcoma, the degree of fatty acyl unsaturation may be an important determinant of the metastatic potential of these tumors. Furthermore, application of TOCSY for the ex vivo study of smooth muscle tumors would potentially serve as a pathologist-independent and quantitative method for assessment of leiomyosarcoma grade and mitotic activity thereby rendering a more accurate staging of patients.     

Effect of a peroxysomal proliferator agent on intracellular cholesterol accumulation in cultured fibroblasts from Niemann-Pick type C disease patients

BACKGROUND: Niemann-Pick type C (NP-C) disease is a lysosomal storage disorder. It is possible that peroxisomes are also modified and their alterations can be an early event in the process of the disease. As the use of peroxisomal inducers restores the original function of the organelle, the importance of peroxisomes is further emphasized and can suggest future therapeutic interventions. METHODS: We treated fibroblast cultures from NP-C patients and normal individuals with 200 and 400 micromol/l clofibrate and evaluated its action on intracellular cholesterol content that was determined by filipin staining and quantitative measurement of unesterified cholesterol. RESULTS: The fibroblasts from NP-C patients that did not receive any drug presented a pattern of intense perinuclear fluorescence associated with the accumulation of unesterified cholesterol which was not observed in normal fibroblasts. Comparing the NP-C fibroblasts that were incubated with clofibrate and the same cells without this treatment, there were no changes in cholesterol content by filipin staining, but normal fibroblasts after incubation with this drug showed a slight increase in its cholesterol content. However, unesterified cholesterol was significantly increased in both cells treated with clofibrate when compared to untreated cells. CONCLUSIONS: Clofibrate is probably not useful for treatment of NP-C patients because it seems to contribute to an increase the cholesterol in the cells of these individuals.     

Effect of gamma-interferon on collagen synthesis by normal and fibrotic human lung fibroblasts.

Increased lung collagen and increased collagen synthesis by lung fibroblasts is well recognized in pulmonary fibrosis. gamma-Interferon has been shown to inhibit collagen synthesis by fibroblasts. To understand its effect on lung fibroblasts we compared how this lymphokine affects the growth and collagen synthesis of normal and fibrotic human lung fibroblasts. The results showed that gamma-IFN inhibited DNA synthesis in all fibroblast strains examined. Both collagen production and type 1 mRNA levels were reduced in three normal and two fibrotic cell strains exposed to gamma-IFN, while they were not affected in one strain from fibrotic lung. Even though an occasional cell was unaffected by the gamma-IFN, collagen mRNA level was reduced in most cells and it remained reduced for 48 h after removing the gamma-IFN. These results show that gamma-IFN inhibits the growth of fibroblast cultures derived from normal and fibrotic human lungs and suppresses collagen synthesis in most of these cells.     

Serotonin and dopamine receptors in the rat pituitary gland: autoradiographic identification, characterization, and localization

S2 serotonin and D2 dopamine receptors were identified, characterized, and localized in rat pituitary gland by quantitative light microscopic autoradiography. [3H]Spiperone was used to localize S2 serotonin and D2 dopamine receptors. A high concentration of D2 dopamine receptors [1 microM 2-amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene (ADTN)- or sulpiride-displaceable [3H]spiperone binding] was found in the rat intermediate lobe with much lower concentrations present in the anterior and posterior lobes. Significant densities of cinanserin-displaceable [3H]spiperone binding sites (i.e. S2 serotonin receptors) were present in all three lobes of the pituitary gland. [125I]Lysergic acid ([125I]LSD) was used to characterize further and selectively visualize S2 serotonin receptors in the rat pituitary. Data analysis by densitometry showed that [125I]LSD binding the rat intermediate pituitary was saturable and of high affinity with an apparent dissociation constant (Kd) of 1.2 nM. Data from competition studies using a variety of compounds showed a S2 serotonin receptor profile at this [125I]LSD binding site in rat pituitary. The highest concentration of [125I]LSD binding sites was found in the intermediate lobe with progressively lower concentrations present in the posterior and anterior lobes, respectively. There is a uniform pattern of distribution of S2 serotonin and D2 dopamine receptors within each lobe of the rat pituitary gland. The results of the present study provide the first identification of S2 serotonin receptors in the pituitary and confirm the heterogeneous distribution of D2 dopamine receptors within the rat pituitary. These data provide further evidence for the importance of dopamine in regulating pituitary function and suggest a physiological role for serotonin in regulating pituitary hormone secretion.     

Characterization and biocompatibility of a fibrous glassy scaffold

Bioactive glasses (BGs) are known for their ability to bond to living bone and cartilage. In general, they are readily available in powder and monolithic forms, which are not ideal for the optimal filling of bone defects with irregular shapes. In this context, the development of BG‐based scaffolds containing flexible fibres is a relevant approach to improve the performance of BGs. This study is aimed at characterizing a new, highly porous, fibrous glassy scaffold and evaluating its in vitro and in vivo biocompatibility. The developed scaffolds were characterized in terms of porosity, mineralization and morphological features. Additionally, fibroblast and osteoblast cells were seeded in contact with extracts of the scaffolds to assess cell proliferation and genotoxicity after 24, 72 and 144 h. Finally, scaffolds were placed subcutaneously in rats for 15, 30 and 60 days. The scaffolds presented interconnected porous structures, and the precursor bioglass could mineralize a hydroxyapatite (HCA) layer in simulated body fluid (SBF) after only 12 h. The biomaterial elicited increased fibroblast and osteoblast cell proliferation, and no DNA damage was observed. The in vivo experiment showed degradation of the biomaterial over time, with soft tissue ingrowth into the degraded area and the presence of multinucleated giant cells around the implant. At day 60, the scaffolds were almost completely degraded and an organized granulation tissue filled the area. The results highlight the potential of this fibrous, glassy material for bone regeneration, due to its bioactive properties, non‐cytotoxicity and biocompatibility. Future investigations should focus on translating these findings to orthotopic applications. Copyright © 2015 John Wiley & Sons, Ltd.