Home About us Contact
|
Home About us Contact | ||
|
|
||
Proline Incorporation (proline + incorporation)
Selected AbstractsEffect of parathyroid hormone-related protein on fibroblast proliferation and collagen metabolism in human skinEXPERIMENTAL DERMATOLOGY, Issue 4 2002Emanuela Maioli Abstract: The parathyroid hormone-related protein (PTHrp), structurally similar to the parathyroid hormone (PTH) in its NH2 -terminal part, was first identified as a tumour-derived peptide responsible for a paraneoplastic syndrome known as humoral hypercalcemia of malignancy. The PTHrp gene is expressed not only in cancer but also in normal tissues during adult and/or fetal life, where it plays predominantly paracrine and/or autocrine roles. In the skin PTHrp produced by keratinocytes acts on fibroblasts by complex cooperative circuits involving cytokines and growth factors. In this report, we studied the direct effects of synthetic PTHrp 1,40 on proliferation and collagen synthesis and matrix metalloproteinase-2 (MMP-2) activity in cultures of fibroblasts isolated from normal human skin. Fibroblasts exposure to varying doses of PTHrp for 48 h, significantly and dose-dependently inhibited proliferation evaluated by [3H]-thymidine incorporation into DNA. A dose-dependent stimulation of cAMP released into the medium was concomitantly observed. In contrast, PTHrp had no effect on collagen synthesis evaluated either by [3H]-proline incorporation or by radioimmunoassay (RIA) of the carboxyterminal fragment of type I procollagen (PICP). MMP-2 activity, evaluated by quantitative zymographic analysis, was significantly increased by PTHrp treatment at doses of 160 and 320 nM. These findings indicate that PTHrp may play a role in normal dermal physiology by controlling both fibroblast proliferation and extracellular matrix degradation. [source] Adenosine reverses a preestablished CCl4 -induced micronodular cirrhosis through enhancing collagenolytic activity and stimulating hepatocyte cell proliferation in ratsHEPATOLOGY, Issue 4 2001Rolando Hernández-Muñoz Cirrhosis is one of the most common causes of mortality worldwide, because hepatic dysfunction constitutes a potentially lethal condition. Having demonstrated the hepatoprotective effect of adenosine against CCl4 -induced cirrhosis, the present study was aimed at assessing adenosine's effect on an already-established micronodular cirrhosis. Chronic administration of CCl4 (10 weeks) induced a cirrhotic state, characterized by increased liver fibronectin and collagen types I and III content, enhanced expression of ,-1 (I) collagen mRNA, portal hypertension, and liver dysfunction. After CCl4 discontinuation (5 weeks), increased persitance of ,-1 (I) collagen mRNA expression and deposition, enhanced proline incorporation into collagen and prolyl hydroxylase activity evidenced active fibrogenesis. Several weeks after CCl4 withdrawal, deposited collagen showed an enhanced type I/III ratio, which was associated with deficient collagenolytic activity in cirrhotic livers. Liver expression of some metalloproteinases (MMPs) and of tissue inhibitors of MMPs (TIMPs) also indicated decreased collagen breakdown in cirrhotic livers. Parameters indicative of oxidative stress (mainly protein oxidation) were persistently augmented. These events were coincident with diminished regenerative capacity of the cirrhotic liver. Intraperitoneal adenosine administration to CCl4 -induced cirrhotic rats blocked active fibrogenesis and increased the collagen degradation (most probably by decreasing liver TIMPs levels), normalizing collagen-type ratios. In addition, the nucleoside promoted an effective hepatocyte's proliferation in the cirrhotic liver and accelerated normalization of parameters indicative of liver function and oxidative stress. Thus, adenosine readily reversed an experimental cirrhosis through stimulating liver collagenolytic and proliferative capacities, as well as by accelerating functional recovery. [source] Insulin-Like Growth Factor I Production Is Essential for Anabolic Effects of Thyroid Hormone in Osteoblasts,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 2 2000Bill K. Huang Abstract Thyroid hormone (T3) and insulin-like growth factor I (IGF-I) are critical regulators of skeletal function. T3 increases IGF-I production in bone. To assess the potential role of IGF-I as a mediator of T3 actions, we characterized phenotypic markers of osteoblast activity in two osteoblast models, normal mouse osteoblasts and MC3T3-E1 cells, exposed to T3 alone or under conditions that interfere with IGF-I actions. T3 significantly increased osteoblast 3H-proline incorporation, alkaline phosphatase (ALP), and osteocalcin. Both ,IR3, a neutralizing monoclonal antibody to the IGF-I receptor, and JB1, an IGF-I analogue antagonist, attenuated the stimulatory effects of T3. T3 effects also were decreased in cells transfected with antisense oligonucleotide (AS-ODN) to the IGF-I receptor gene. Both IGF-I and T3 had mitogenic effects that were inhibited by the antagonists. IGF-I by itself did not stimulate 3H-proline incorporation, ALP, and osteocalcin in the models used, revealing that although IGF-I is essential for the anabolic effects of T3, it acts in concert with other factors to elicit these phenotypic responses. (J Bone Miner Res 2000;15:188,197) [source] High glucose increase cell cycle regulatory proteins level of mouse embryonic stem cells via PI3-K/Akt and MAPKs signal pathwaysJOURNAL OF CELLULAR PHYSIOLOGY, Issue 1 2006Yun Hee Kim This study examined the effects of high glucose on cell proliferation and its related signal pathways using mouse embryonic stem (ES) cells. Here, we showed that high glucose level significantly increased [3H]thymidine incorporation, BrdU incorporation, the number of cells, [3H]leucine, and [3H]proline incorporation in a time-(>3 hr) and dose-(>25 mM) dependent manner. Moreover, high glucose level increased the cellular reactive oxygen species (ROS), Akt, and mitogen-activated protein kinases (MAPKs) phosphorylation. Subsequently, these signaling molecules involved in high glucose-induced increase of [3H]thymidine incorporation. High glucose level also increased cyclin D1, cyclin E, cyclin-dependent kinase (CDK) 2, and CDK 4 protein levels, which is cell cycle regulatory proteins acting in G1,S phase of cell cycle. Inhibition of phosphatidylinositol 3-kinase (PI3-K) (LY 294002: PI3-kinase inhibitor, 10,6 M), Akt (Akt inhibitor, 10,5 M), and p44/42 MAPKs (PD 98059: MEK inhibitor, 10,5 M) decreased these proteins. High glucose level phosphorylated the RB protein, which was decreased by inhibition of PI3-K and Akt. In conclusion, high glucose level stimulates mouse ES cell proliferation via the PI3-K/Akt and MAPKs pathways. J. Cell. Physiol. 209: 94,102, 2006. © 2006 Wiley-Liss, Inc. [source] Specific Determination of Endothelial Cell Viability in the Whole Cell Fraction from Cryopreserved Canine Femoral Veins Using Flow CytometryARTIFICIAL ORGANS, Issue 10 2000Jong-Chul Park Abstract: An efficient method for specifically determining the viability of endothelial cells (EC) from cells dissociated from the human saphenous vein was investigated. Three different methods, trypan blue staining assay, [3H]-proline incorporation assay, and flow cytometry (FCM), combined with the fluorescein isothiocyanate conjugated with Griffonia simplicifolia agglutins (GS1-FITC)/propidium iodide (PI) double staining, were used. Both trypan blue staining and [3H] proline incorporation assays demonstrated less sensitivity to determine viability of EC differentially from the other cells. FITC-GS1 showed prominent binding to the vascular EC and could be counted by FCM including PI on dead cells. Following the cryopreservation process, the GS1-FITC/PI FCM analytical method was adopted to test simultaneously the viability of whole cells and EC from the same tissue, human saphenous veins, and mongrel dogs' femoral veins after harvesting, antibiotic solution treatment, and thawing. The viability of the whole cells from veins decreased with a significant difference (p < 0.05) from that of EC after thawing. [source] | ||||||||||