Search Results

Multiple myeloma (MM) is the most common malignancy arising from plasma cells, fully differentiated B lymphocytes that produce the immunoglobulin (Ig) heavy- and light-chain molecules comprising antibodies. MM is characterized by an overproduction of clonal plasma cells in the bone marrow and, in most cases, monoclonal secretion of IgG, IgA, or light-chain Ig. Symptoms of end organ damage (hypercalcemia [C], renal failure [R], anemia [A], or bone lesions [B]), herein referred to as CRAB features, were traditionally a necessary criterion for diagnosing MM; however, improvements in treatment and diagnostic techniques have led to updated diagnostic criteria, enabling intervention among patients before the onset of organ damage. Multiple myeloma is an important cause of lymphoid malignancy (LM) mortality in Western populations. In the United States in 2015, MM was estimated to account for approximately one in every five newly diagnosed LMs, and one in every three LM-related deaths.

Most invasive dental procedures involving removal of teeth or bone are followed by uneventful healing. However, dentists should be aware that generalized abnormalities of bone, such as osteoporosis and Paget’s dis­ease of bone, may complicate these procedures and, rarely, can lead to ongoing clinical problems. The effects of radiotherapy to the jaws and bisphosphonate treatment are well-described causes of osteonecrosis and delayed healing. Diagnosis of bone disorders often depends on integrating the results of clinical, imaging, pathological, genetic, and biochemical investigations. Although the bony skeleton is often thought of as forming just a rigid framework, it should be remembered that bone is a living, responsive tissue that plays an important role in metabolism. During development, some bones develop from a cartilaginous template and others, such as most of the craniofacial bones, form in fibrous membranes. Bone matrix is laid down by osteoblasts that are derived from the extensive meshwork of bone-lining cells that cover the bone surfaces. The bone matrix contains osteocytes that are responsive to mechanical stresses. Bone matrix is removed by osteoclasts that move over the bone sur­face, resulting in scalloped pits termed Howship’s lacunae. Bone mat­rix can be woven or lamellar in pattern. Pathologists often examine sections of bony lesions in polarized light to determine whether the pattern of the collagenous matrix is woven or lamellar, because it can be pivotal for diagnosis. It is also important for clinicians to be aware that, in order to produce a histological section of bone, the tissue must first be fixed and then demineralized to soften the matrix. When a bone biopsy is performed, the patient should be made aware that additional time will be needed to process the biopsy. Following extraction of a tooth, the socket rapidly fills with blood, which then clots. Granulation tissue, which consists of proliferating endothelial cells and fibroblasts derived from remnants of the periodontal ligament and surrounding alveolar bone, grows into the clot and organization commences. Osteoclasts begin to remodel the crestal bone and remove any small spicules of bone detached during the extraction.

Questions

The four parathyroid glands play a key role in calcium homeostasis by secreting parathyroid hormone (PTH).

Which one of the following statement regarding parathyroid gland/PTH physiology is correct?

1, 25-dihydoxy vitamin D is the main storage form of vitamin D

Parathyroid glands develop...