Bone marrow tissue typing

Dendritic cells (DC) are important antigen-presenting cells mostly derived from the bone marrow. Microscopically they show characteristic long cytoplasmic extensions called dendrites. There are several types of specialized DC present in all lymphoid tissues and major... 

Bone marrow Blood Peripheral tissue Lymph Lymph node Type of... 

The absorption efficiency term allows estimation of the effective dose or the amount of pollutant which crosses the membrane of the exposed tissue (e.g., the lung) and reaches a target organ (e.g., the liver). For many pollutants this type of metabolic data is not available and consequently 100% absorption is a common preliminary assumption in exposure assessments. For well-studied substances such as radionuclides, a methodology for calculation of target organ doses has been developed for bone marrow, lungs, endosteal cells, stomach wall, lower intestine wall, thyroid, liver, kidney, testes and ovaries as well as for the total body. 

For many years it was believed that adult stem cell populations were present in a very limited number of tissue types, and that they could only differentiate into cells characteristic of the tissue in which they reside. Recent research challenges both of these assertions. Adult stem cells are being discovered in a growing number of tissues, including bone marrow, peripheral blood and... 

The brain stores and releases histamine from more than one type of cell. Mast cells are a family of bone marrow-derived secretory cells that store and release high concentrations of histamine. They are found throughout many connective tissues of the body, but are also present within and surrounding the brain of many species [4,5], In many... 

Immunopathology Enumeration of T and B cells and subsets immunocyto-chemistry of lymphoid tissues inumeration of cell types and numbers in the bone marrow... 

Bone Marrow The soft tissue filling the cavities of bones. Bone marrow exists in two types, yellow and red. Yellow marrow is found in the large cavities of large bones and consists mostly of fat cells and a few primitive blood cells. Red marrow is a hematopoietic tissue and is the site of production of erythrocytes and granular leukocytes. Bone marrow is made up of a framework of connective tissue containing branching fibers with the frame being filled with marrow cells. [NIH]... 

There are many causes of the clinical condition referred to as anaemia. One particular type, whose cause can be traced to a genuine metabolic defect is megaloblastic anaemia and is due to a deficiency of the vitamins B12 (cobalamin) and/or folate. These vitamins are required for normal cell division in all tissues, but the rapid production of red cells makes them more susceptible to deficiency. In megaloblastic anaemia the blood haemoglobin concentration falls the synthesis of haem is not impaired. Examination of the blood reveals the appearance of larger then normal cells called macrocytes and megaloblasts are found in the bone marrow. 

The various cell types are distributed differently within various types of connective tissue fibroblasts often found lying close to collagen fibres, whilst macrophages and mast cells usually appear in clusters around blood vessels. Additionally, whereas fibroblasts are widespread, macrophages are absent from some types of connective tissue, tendons for example. Specialized cells also occur within particular locations for example osteoblasts and osteoclasts (bone), chondrocytes (cartilage), adipocytes (fat tissue) and haemopoietic cells (bone marrow). 

Bone marrow is the spongy tissue inside the cavities of our bones. Bone marrow stem cells grow and divide into the various types of blood cells white blood cells (leukocytes) that fight infection, red blood cells (erythrocytes) that transport oxygen, and platelets that are the agents for clotting. 

In order to prepare the bone marrow alogenic transplantation the selection of histocompatible donor-recipient pair was carried out by HLA system in the laboratory of tissue typing. 136 recipients and 212 relative donors were inspected during 5 years of work. 

In addition to fully differentiated cells, many tissues of the body contain stem cells - precursor cells that are not fully differentiated. These can divide to produce more stem cells but can also give rise to progeny which can differentiate. Stem cells in the bone marrow, for example, give rise to all the different types of immune cells, erythrocytes and megakaryocytes, which give rise to platelets. 

Hematopoiesis, the process of generating mature blood cells, is mainly located in the red bone marrow, predominantly in the sternum, femur and pelvic bones [1]. In the marrow the hematopoietic cells are embedded in stromal tissue. This consists of different cell types (e.g., fibroblasts, endothehal cells, adipocytes, macrophages) that provide soluble and membrane-bound growth factors and produce an extracellular matrix consisting of collagen, laminin, fibronectin, and glycosaminoglycans [2, 3]. The interactions between hematopoietic cells, stromal cells and extracellular matrix are indicated in Fig. 1 [4,5]. 

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