Harrison Interal Medicine
Chapter 067. Applications of Stem Cell Biology in Clinical Medicine (Part 1)
Harrison's Internal Medicine Chapter 67. Applications of Stem Cell Biology in Clinical Medicine Applications of Stem Cell Biology in Clinical Medicine: Introduction Organ damage and the resultant inflammatory responses initiate a series of repair processes, including stem cell proliferation, migration, and differentiation, often in combination with angiogenesis and remodeling of the extracellular matrix. Endogenous stem cells in tissues such as liver and skin have a remarkable ability to regenerate the organs, whereas heart and brain have a much more limited capability for self-repair. Under rare circumstances, circulating stem cells may contribute to regenerative responses by migrating into a tissue...
5 trang Chia sẻ: konheokonmummim Ngày:03-12-2010 |Xem: 29 |Download:11
Chapter 064. The Practice of Genetics in Clinical Medicine (Part 1)
Harrison's Internal Medicine Chapter 64. The Practice of Genetics in Clinical Medicine Implications of Molecular Genetics for Internal Medicine The field of medical genetics has traditionally focused on chromosomal abnormalities (Chap. 63) and Mendelian disorders (Chap. 62). However, there is genetic susceptibility to many common adult-onset diseases, including atherosclerosis, cardiac disorders, asthma, hypertension, autoimmune diseases, diabetes mellitus, macular degeneration, Alzheimer's disease, psychiatric disorders, and many forms of cancer. Genetic contributions to these common disorders involve more than the ultimate expression of an illness; these genes can also influence the severity of infirmity, effect of treatment, and progression of disease. ...
5 trang Chia sẻ: konheokonmummim Ngày:03-12-2010 |Xem: 28 |Download:8
Chapter 067. Applications of Stem Cell Biology in Clinical Medicine (Part 4)
Other Organ Systems and the Future The use of stem cells in regenerative medicine has been studied for many other organ systems and cell types, including skin, eye, cartilage, bone, kidney, lung, endometrium, vascular endothelium, smooth muscle, striated muscle, and others. In fact, the potential for stem cell regeneration of damaged organs and tissues is virtually limitless. However, numerous obstacles must be overcome before stem cell therapies can become a widespread clinical reality. Only HSCs have been adequately characterized by surface markers to allow unambiguous identification, a prerequisite for reliable clinical applications. The pathways for differentiating stem cells into...
5 trang Chia sẻ: konheokonmummim Ngày:03-12-2010 |Xem: 34 |Download:7
Chapter 066. Stem Cell Biology (Part 1)
Harrison's Internal Medicine Chapter 66. Stem Cell Biology Stem Cell Biology: Introduction Stem cell biology is a relatively new field that explores the characteristics and possible clinical applications of the different types of pluripotential cells that serve as the progenitors of more differentiated cell types. In addition to potential therapeutic applications (Chap. 67), patient-derived stem cells can also provide disease models and a means to test drug effectiveness. Identification, Isolation, and Derivation of Stem Cells Resident Stem Cells The definition of stem cells remains elusive. Stem cells were originally postulated as unspecified or undifferentiated cells that provide a source of renewal of skin, intestine,...
9 trang Chia sẻ: konheokonmummim Ngày:03-12-2010 |Xem: 51 |Download:15
Chapter 068. Hematopoietic Stem Cells (Part 1)
Harrison's Internal Medicine Chapter 68. Hematopoietic Stem Cells Hematopoietic Stem Cells: Introduction All of the cell types in the peripheral blood and some cells in every tissue of the body are derived from hematopoietic (hemo: blood; poiesis: creation) stem cells. If the hematopoietic stem cell is damaged and can no longer function (e.g., due to the nuclear accident at Chernobyl), a person would survive 2–4 weeks in the absence of extraordinary support measures. With the clinical use of hematopoietic stem cells, tens of thousands of lives are saved each year (Chap. 108). Stem cells produce tens of billions of...
5 trang Chia sẻ: konheokonmummim Ngày:03-12-2010 |Xem: 27 |Download:10
Chapter 064. The Practice of Genetics in Clinical Medicine (Part 2)
Population Screening Mass genetic screening programs require tests of high enough sensitivity and specificity to be cost-effective. An effective screening program should fulfill the following criteria: that the tested disorder is prevalent and serious; that it can be influenced presymptomatically through lifestyle changes, screening, or medications; and that identification of risk does not result in undue discrimination or harm. Screening individuals of Jewish descent for the autosomal recessive neurodegenerative disorder Tay-Sachs disease has resulted in a dramatic decline in the incidence of this syndrome in the United States. On the other hand, screening for sickle cell disease or trait...
5 trang Chia sẻ: konheokonmummim Ngày:03-12-2010 |Xem: 24 |Download:10
Chapter 067. Applications of Stem Cell Biology in Clinical Medicine (Part 3)
Diabetes Mellitus The success of islet cell and pancreas transplantation provides proof of concept for a cell-based approach for type I diabetes. However, the demand for donor pancreata far exceeds the number available, and maintenance of long-term graft survival remains a problem. The search for a renewable source of stem cells capable of regenerating pancreatic islets has therefore been intensive. Pancreatic βcell turnover occurs in the normal pancreas, although the source of the new βcells is controversial. Attempts to promote endogenous regenerative processes have not yet been successful, but this remains a potentially viable approach. A number of different cell...
5 trang Chia sẻ: konheokonmummim Ngày:03-12-2010 |Xem: 38 |Download:9
Chapter 067. Applications of Stem Cell Biology in Clinical Medicine (Part 2)
Strategies for Stem Cell Replacement Stem cell transplantation is not a new concept and it is already part of established medical practice. Hematopoietic stem cells (HSCs) (Chap. 68) are responsible for the long-term repopulation of all blood elements in bone marrow transplant recipients. HSC transplantation is now the gold standard against which other stem cell transplantation therapies will be measured. Transplantation of differentiated cells is also a clinical reality, as donated organs (e.g., liver, kidney) and tissues (i.e., cornea, eye, skin) are often used to replace damaged tissues. However, the clinical need for transplantable tissues and organs far outweighs...
5 trang Chia sẻ: konheokonmummim Ngày:03-12-2010 |Xem: 29 |Download:8
Chapter 064. The Practice of Genetics in Clinical Medicine (Part 6)
Follow-Up Care after Testing Depending on the nature of the genetic disorder, posttest interventions may include (1) cautious surveillance and appropriate health care screening, (2) specific medical interventions, (3) chemoprevention, (4) risk avoidance, and (5) referral to support services. For example, patients with known pathologic mutations in BRCA1 or BRCA2 are offered intensive screening as well as the option of prophylactic mastectomy and oophorectomy. In addition, such women may be eligible for preventive treatment with tamoxifen, or enrollment in a chemoprevention clinical trial. In contrast, those at known risk for Huntington's disease are offered continued follow-up and supportive services,...
6 trang Chia sẻ: konheokonmummim Ngày:03-12-2010 |Xem: 21 |Download:8
Chapter 075. Evaluation and Management of Obesity (Part 1)
Harrison's Internal Medicine Chapter 75. Evaluation and Management of Obesity Evaluation and Management of Obesity: Introduction Over 66% of U.S. adults are currently categorized as overweight or obese, and the prevalence of obesity is increasing rapidly throughout most of the industrialized world. Based on statistics from the World Health Organization, overweight and obesity may soon replace more traditional public health concerns such as undernutrition and infectious diseases as the most significant contributors to ill health. Children and adolescents are also becoming more obese, indicating that the current trends will accelerate over time. Obesity is associated with an increased risk...
12 trang Chia sẻ: konheokonmummim Ngày:03-12-2010 |Xem: 24 |Download:7