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Sunday, November 11, 2012

Molecular profiling in multiple myeloma Broyl, A. Multiple Myeloma (MM) is a malignant plasma cell disorder accounting for 1% of all malignant diseases and 10% of hematological malignancies. The annual incidence world-wide of MM is approximately 0.4 to 5 per 100.000, with high incidence rates in North America, Australia/New Zealand, Northern Europe, and Western Europe compared with Asian countries. Within the United States, the incidence in African Americans is about double that in Caucasians, whereas persons of Japanese and Chinese origin have lower rates. In the Netherlands the annual incidence of MM is 5 per 100.000 and increases progressively with age, the median age of diagnosis is 70 years. MM is characterized by clonal expansion of malignant plasma cells in the bone marrow. The myeloma plasma cell is a post-germinal centre plasma cell which has undergone somatic hypermutation and immunoglobulin class switching. MM cells secrete a monoclonal protein (M-protein) which can be detected in serum and/or urine. The M-protein is IgG in 50% of patients, and IgA in 30% of patients or consists of light chain (15%). In rare cases, secretion of IgD (1%–2%), IgM (0.2%), or IgE (even less frequent), or absence of secretion (non-secretory MM) is found. Osteolytic bone lesions are the hallmark of MM. Other characteristic clinical features include renal injury, anemia, hypercalcemia and immunodeficiency with recurrent infections. These features may result directly from mass accumulation of plasma cells in tissues (plasmacytomas) or indirectly from effects of the M-protein and/or cytokines secreted by the plasma cells. Furthermore a high level of M-protein can cause hyperviscosity, renal failure and neuropathy.

Genetic determinants of Von Willebrand factor and the risk of cardiovascular disease Loon, J.E. van

Normal haemostasis requires a delicate balance between procoagulant and anticoagulant factors. Disruption of this balance may lead to bleeding disorders, such as hemophilia, or thrombotic disorders, including deep vein thrombosis of the leg. As Virchow already reported in 1877, properties of the blood vessel wall, the blood flow and blood constituents contribute to the formation of thrombi in either veins or arteries. However, through contemporary research the complexity of this process leading to thrombus formation has become more apparent. An important player in thrombus formation is von Willebrand Factor (VWF), a large multifunctional glycoprotein. VWF initiates adherence of platelets to the injured vessel wall and subsequent platelet aggregation leading inevitably to the formation of thrombi. In addition, VWF is a carrier protein of coagulation factor VIII (FVIII), thereby protecting it from clearance. In healthy subjects normal plasma VWF levels range from 0.60 – 1.40 IU/mL and are characterized by a large variation. This can be partly attributed to a number of lifestyle and environmental factors, but most importantly to genetic factors. The necessity of maintaining normal VWF levels in the circulation is illustrated by two clinical manifestations that may occur when VWF exceeds its normal range. Low levels of VWF may lead to bleeding, which is known as von Willebrand Disease (VWD), the most common inherited bleeding disorder in humans. To the contrary, high VWF antigen (VWF:Ag) levels are associated with an increased risk of venous thrombosis and arterial thrombosis, including myocardial infarction (MI) and ischemic stroke.

Short Adolescents Born Small for Gestational Age : Gonadal and thyroid function, bone mineral density, quality of life and adult height: The effects of growth hormone and additional postponement of puberty Lem, A.J.

From 1991, our research group and others have been investigating children with short stature who were born small for gestational age (SGA), both before and during treatment with biosynthetic growth hormone (GH). In 2005, GH treatment was licensed for short SGA children in the Netherlands. Many questions though remained unanswered, especially about the efficacy of GH treatment when started at an older age, just before or during puberty. This doctoral thesis describes studies evaluating short adolescents born SGA who were treated with GH, and additionally with postponement of puberty by gonadotropin-releasing hormone analogue (GnRHa).