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.

Special issue: honoring George A. Olah at 90

Abstract: This collection of contributions honors George A. Olah on the occasion of his 90th birthday.

Classic image: peripheral blood smear in a case of Plasmodium falciparum cerebral malaria

Abstract: A 29-year-old African-American woman presented with acute onset of altered mental status. She was obtunded with visible rigors and a fever of 102.8°F. Routine laboratory study showed platelet count of 59k/mm3. Urine toxicology screening, blood alcohol level and cerebrospinal fluid analysis were within normal limits. CT of the head was non-revealing. A Giemsa-stained peripheral blood smear (figure 1) was obtained which showed many red blood cells (RBCs) infected with classic, ring-shaped (arrow A) and headphone-shaped (arrow B) …

Chapter 46 – Platelet-Derived Growth Factor and the Skeleton

Abstract: Publisher Summary This chapter focuses on the effects of platelet-derived growth factor (PDGF) on the skeleton. PDGFis a polypeptide with a molecular mass of 30 kDa, which is composed of two polypeptide chains, and may be combined in a homodimeric or heterodimeric form. PDGF was initially isolated from human platelets, but subsequently its presence was found in selected tissues, including bones. In the circulation, PDGF is transported in platelet granules, where its composition is 70% PDGF AB heterodimer, 25% PDGF BB, and 5% PDGF AA homodimer. As PDGF is present in platelets and is expressed by various cell types, it is considered to act both as a systemic and as a local regulator of cell metabolism. Osteoblasts and osteosarcoma cell lines synthesize PDGF, and these cells express the PDGF A and B genes. PDGF stimulates bone cell replication and DNA synthesis, both in intact calvariae and in isolated rat osteoblasts. The primary effect of PDGF in bone is related to its mitogenic activity and it increases the number of cells capable of synthesizing collagen. IGFs stimulate bone collagen synthesis and matrix apposition rates, whereas BMPs induce the differentiation of immature cells into cells of the osteoblastic lineage and stimulate the function of mature osteoblasts. In addition to its effects on bone formation, PDGF increases bone resorption and collagen degradation. This effect is secondary to an increase in the expression of the matrix metalloproteinases (MMP), collagenase 1 and 3. An increase in MMP expression by PDGF has also been observed in nonskeletal fibroblasts. PDGF increases osteoclast number in calvariae, which could be due to an increase in osteoclastogenesis or a decrease in osteoclast apoptosis.