Saint Francis University

About: Saint Francis University is a education organization based out in Loretto, Pennsylvania, United States. It is known for research contribution in the topics: Population & Osteoblast. The organization has 1694 authors who have published 2038 publications receiving 87149 citations.

Transcriptional and posttranscriptional regulation of interstitial collagenase by platelet-derived growth factor BB in bone cell cultures.

Abstract: Platelet-derived growth factor (PDGF), a bone cell mitogen, stimulates bone collagen degradation and does not enhance bone matrix apposition rates. The mechanism of the effect on collagen degradation is unknown, and it could involve changes in interstitial collagenase synthesis. We tested the effects of PDGF on interstitial collagenase expression in cultures of osteoblast-enriched cells from fetal rat calvariae (Ob cells). After 4-8 h of treatment, PDGF BB at 0.3 nM increased steady state collagenase messenger RNA (mRNA), whereas PDGF AA had no effect. The effect of PDGF BB on collagenase transcripts was dose dependent. PDGF BB increased the levels of immunoreactive collagenase after 6 h, whereas the levels were decreased after 16 h. Stimulation of collagenase mRNA by PDGF BB was dependent on de novo protein synthesis and activation of protein kinase C. PDGF BB prolonged the half-life of collagenase mRNA in transcriptionally arrested cells. PDGF BB initially increased and subsequently decreased the rate o...

Clinical use of a commercial Monte Carlo treatment planning system for electron beams.

Abstract: In 2002 we fully implemented clinically a commercial Monte Carlo based treatment planning system for electron beams. The software, developed by MDS Nordion (presently Nucletron), is based on Kawrakow's VMC++ algorithm. The Monte Carlo module is integrated with our Theraplan Plustrade mark treatment planning system. An extensive commissioning process preceded clinical implementation of this software. Using a single virtual 'machine' for each electron beam energy, we can now calculate very accurately the dose distributions and the number of MU for any arbitrary field shape and SSD. This new treatment planning capability has significantly impacted our clinical practice. Since we are more confident of the actual dose delivered to a patient, we now calculate accurate three-dimensional (3D) dose distributions for a greater variety of techniques and anatomical sites than we have in the past. We use the Monte Carlo module to calculate dose for head and neck, breast, chest wall and abdominal treatments with electron beams applied either solo or in conjunction with photons. In some cases patient treatment decisions have been changed, as compared to how such patients would have been treated in the past. In this paper, we present the planning procedure and some clinical examples.

Bone morphogenetic protein-4 regulates its own expression in cultured osteoblasts.

Abstract: During development, bone morphogenetic proteins (BMPs) induce the differentiation of mesenchymal progenitor cells to enter into the osteoblastic lineage, and BMPs enhance osteoblastic function. BMPs and noggin, a specific binding protein that blocks BMP actions, are expressed by osteoblastic cells but there is limited information about regulation of BMP synthesis in skeletal cells. We tested for the expression and regulation of BMP-4 in cultures of osteoblast-enriched cells from 22-day fetal rat calvariae (Ob cells). BMP-4 caused a short-lived increase in BMP-4 mRNA followed by a marked inhibition of BMP-4 expression. The stimulatory effect was transcriptional, as determined by nuclear run-on assays, whereas the inhibitory effect was transcriptional and posttranscriptional, because longer BMP-4 exposure decreased its rate of transcription and shortened the half-life of BMP-4 mRNA in transcriptionally arrested Ob cells. BMP-2 and BMP-6 also inhibited BMP-4 mRNA levels. Transforming growth factor beta1 increased, whereas fibroblast growth factor-2, platelet-derived growth factor BB, and insulin-like growth factor I decreased BMP-4 mRNA in Ob cells. BMP-2 also was expressed by Ob cells and it was downregulated by BMP-2, BMP-4, and BMP-6. Noggin increased BMP-4 transcripts, suggesting autocrine control of BMP-4 expression. In conclusion, BMP-4 inhibits its own expression in Ob cells, a mechanism to limit BMP availability to osteoblasts.

Binding of immunoglobulin G from patients with autoimmune thyroid disease to rat sodium-iodide symporter peptides: evidence for the iodide transporter as an autoantigen.

Abstract: The recent cloning of the rat sodium-iodide symporter (rNIS) from FRTL-5 cells makes possible studies of the role of this thyroid-specific protein as an antigen in autoimmune diseases of the thyroi...