The patient is being considered for hematopoietic cell transplantation cheap imitrex 25mg without a prescription. Which of the following statements regarding hematopoietic cell transplantation is false? Hematopoietic stem cells for transplantation may derive from bone marrow cheap 25 mg imitrex, peripheral blood cheap 25 mg imitrex overnight delivery, or umbilical cord blood B. Syngeneic transplantations come from identical twins; identical twins are the best possible donors of stem cells C. In allogeneic transplantations, if two persons do not share the same HLA antigens, B cells taken from one person will react vigorously to the mismatched HLA molecules on the surface of the cells from the other person D. When compared with allogeneic transplantation, autologous trans- plantation has the advantage of avoiding graft versus host disease (GVHD) and associated complications Key Concept/Objective: To understand the different types of hematopoietic stem cell transplantations Hematopoietic stem cell transplantation can be categorized according to the relation between the donor and the recipient and according to the anatomic source of the stem cell. Hematopoietic stem cells for transplantation may derive from bone marrow, peripheral blood, or umbilical cord blood and may be harvested from a syngeneic, allogeneic, or 5 HEMATOLOGY 27 autologous donor. Identical twins are the best possible donors of stem cells. When syn- geneic donors are used, neither graft rejection nor GVHD will develop in the recipient. Only about one in 100 patients undergoing transplantation will have an identical twin. Allogeneic transplantation, which involves a related or unrelated donor, is more compli- cated than syngeneic or autologous transplantation because of immunologic differences between donor and host. With allogeneic hematopoietic cell transplantation, in which the immune system of the patient is provided by the graft, the clinical concerns are not only with the prevention of graft rejection by host cells surviving the pretransplant preparative regimen but also with the prevention of donor cells from causing immune-mediated injury to the patient (i. Immunologic reactivity between donor and host is large- ly mediated by immunocompetent cells that react with HLAs, which are encoded by genes of the major histocompatibility complex. HLA molecules display both exogenous peptides (for example, from an infecting virus) and endogenous peptides, presenting them to T cells, an important step in the initiation of an immune response. If two persons do not share the same HLA antigens, T cells taken from one person will react vigorously to the mismatched HLA molecules on the surface of the cells from the other.
In most patients with SBE order 50 mg imitrex, blood cultures drawn before initiation of antibiotic therapy are positive discount imitrex 50 mg mastercard, reflecting the sustained bacteremia associ- ated with an infected endothelial surface purchase 50mg imitrex amex. Factors associated with an increased risk of embolization include vegetations of 10 mm or more in size as seen on echocardiogra- phy; vegetations on the mitral valve, particularly the anterior leaflet; vegetations that increase in size during therapy; and infection by Staphylococcus aureus. The incidence of arterial emboli decreases about 10-fold during the initial 2 weeks of antimicrobial therapy. A 35-year-old man presents in the urgent care clinic complaining of fever. He reports that for the past 2 days, he has been experiencing subjective fever, shaking chills, and pleuritic chest pain. The patient denies having any underlying medical conditions. Results of physical examination are as follows: temperature, 103. The neck veins are flat, and the heart is tachycardic with a short systolic ejection murmur that is louder on inspiration. For this patient, which of the following statements about infective endocarditis in intravenous drug users (IDUs) is true? The mitral valve is the most commonly involved valve B. The majority of IDUs who develop endocarditis have preexisting valvular heart disease C. An empirical antibiotic regimen need not include vancomycin because the patient has not been exposed to the health care system recently D. The majority of IDUs with right-sided endocarditis have septic pul- monary emboli 56 BOARD REVIEW Key Concept/Objective: To know the common features of endocarditis in IDUs The annual incidence of endocarditis in IDUs is 0. At the time of their ini- tial attack of endocarditis, 70% to 80% of IDUs have no history or findings of preexist- ing valvular heart disease.
The disease’s cause is unknown IONS Electrically charged atoms or molecules imitrex 25 mg visa. NERVE GROWTH FACTOR A substance whose role is to guide LONG-TERM MEMORY The ﬁnal phase of memory in which neuronal growth during embryonic development discount 50 mg imitrex overnight delivery, especially information storage may last from hours to a lifetime cheap imitrex 25 mg on-line. Nerve growth factor also 50 probably helps sustain neurons in the adult. It is specialized for the transmission of act and is often the result of second messenger activity. In called axons and shorter, branch-like projections called some animals, the pineal gland serves as a light-inﬂuenced dendrites. NEUROTRANSMITTER A chemical released by neurons at a PITUITARY GLAND An endocrine organ closely linked with the synapse for the purpose of relaying information to other hypothalamus. In humans, the gland is composed of two lobes neurons via receptors. PONS A part of the hindbrain that, with other brain struc- NOREPINEPHRINE A catecholamine neurotransmitter, pro- tures, controls respiration and regulates heart rhythms. The duced both in the brain and in the peripheral nervous system. OCCIPITAL LOBE One of the four subdivisions of the cerebral PSYCHOSIS A severe symptom of mental disorders character- cortex. The occipital lobe plays a role in processing visual ized by an inability to perceive reality. RECEPTOR CELL A specialized sensory cell designed to pick up PARASYMPATHETIC NERVOUS SYSTEM A branch of the auto- and transmit sensory information. Many neurotransmitters and hormones exert their cortex. The parietal lobe plays a role in sensory processes, e∑ects by binding to receptors on cells. REUPTAKE A process by which released neurotransmitters are PARKINSON’S DISEASE A movement disorder caused by death absorbed for subsequent reuse.