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Query: UMLS:C0015674 (chronic fatigue syndrome)
 2,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This article summarizes (1) epidemiologic and clinical data on the symptoms of maladies in association with low-level chemicals in the environment, i.e., environmental chemical intolerance (CI), as it may relate to chronic fatigue syndrome (CFS) and fibromyalgia; and (2) the olfactory-limbic neural sensitization model for CI, a neurobehavioral synthesis of basic and clinical research. Severe CI is a characteristic of 20-47% of individuals with apparent CFS and/or fibromyalgia, all patients with multiple chemical sensitivity (MCS), and approximately 4-6% of the general population. In the general population, 15-30% report at least minor problems with CI. The levels of chemicals reported to trigger CI would normally be considered nontoxic or subtoxic. However, host factors--e.g., individual differences in susceptibility to neurohormonal sensitization (amplification) of endogenous responses--may contribute to generating a disabling intensity to the resultant multisystem dysfunctions in CI. One site for this amplification may be the limbic system of the brain, which receives input from the olfactory pathways and sends efferents to the hypothalamus and the mesolimbic dopaminergic [reward] pathway. Chemical, biologic, and psychological stimuli can initiate and elicit sensitization. In turn, subsequent activation of the sensitized limbic and mesolimbic pathways can then facilitate dysregulation of behavioral, autonomic, endocrine, and immune system functions. Research to date has demonstrated the initiation of neurobehavioral sensitization by volatile organic compounds and pesticides in animals, as well as sensitizability of cardiovascular parameters, beta-endorphin levels, resting EEG alpha-wave activity, and divided-attention task performance in persons with CI. The ability of multiple types of widely divergent stimuli to initiate and elicit sensitization offers a new perspective on the search for mechanisms of illness in CFS and fibromyalgia with CI.
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PMID:Illness from low levels of environmental chemicals: relevance to chronic fatigue syndrome and fibromyalgia. 979 Apr 86

Patients with multiple chemical sensitivities (MCS) often report heightened sensitivity to odors. Odor detection thresholds to phenyl ethyl alcohol (PEA) and pyridine (PYR) were evaluated as a measure of odor sensitivity for 33 MCS subjects, 13 chronic fatigue syndrome subjects, 16 asthmatic subjects, and 27 healthy controls. Odor identification ability (based on University of Pennsylvania Smell Identification Test results) and ratings in response to four suprathreshold levels of PEA and PYR were also assessed. Odor detection thresholds for PEA and PYR and odor identification ability were equivalent for all groups; however, when exposed to suprathreshold concentrations of PEA, MCS subjects reported significantly more trigeminal symptoms and lower esthetic ratings of PEA. No group differences were found in response to suprathreshold concentrations of PYR. In summary, MCS subjects did not demonstrate lower olfactory threshold sensitivity or enhanced ability to identify odors accurately. Furthermore, they were differentiated from the other groups in their symptomatic and esthetic ratings of PEA, but not PYR.
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PMID:Odor perception: multiple chemical sensitivities, chronic fatigue, and asthma. 1087 56

Sensitivities to chemicals are characterized by symptoms in multiple organ systems in response to low-level chemical exposures. This paper reviews studies of controlled exposures to odorants and to mixtures of volatile organic compounds. Sensitive subgroups include subjects who met Cullen's 1987 criteria for multiple chemical sensitivity (MCS), Gulf War veterans with chronic fatigue syndrome and chemical sensitivity (CFS/CS), and subjects with specific self-reported sensitivities to methyl terbutyl ether (MTBE) in gasoline (MTBE-sensitive). All studies include comparison of age- and sex-matched healthy controls. Studies of olfaction did not support unusual sensitivity, defined as lower odor thresholds, among MCS subjects; however, a dose-response pattern of symptoms was observed in response to suprathreshold concentrations of phenyl ethyl alcohol. In blinded, controlled exposures to clean air, gasoline, gasoline/11% MTBE, and gasoline/15% MTBE, a threshold effect was observed with MTBE-sensitive subjects reporting significantly increased symptoms to gasoline/15% MTBE exposure. Autonomic arousal (heart and respiration rate; end-tidal CO2) in response to odor of chemical mixtures may mediate symptoms for subjects with generalized chemical sensitivities, but not for those whose sensitivities are confined to specific chemicals. For example, Gulf War veterans with CFS/CS experienced reduced end-tidal CO2 when exposed to diesel fumes, while exposure to MTBE did not produce any psychophysiologic changes in MTBE-sensitive subjects. Controlled olfactory and exposure studies reveal that significant responses can be observed in chemically sensitive subjects even when de-adaptation has not occurred. However, these studies suggest that symptoms are not necessarily accompanied by changes in physiologic arousal. Subject characteristics play a critical role in outcomes.
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PMID:Controlled exposures to volatile organic compounds in sensitive groups. 1200 25

In 2005 we reported that transplanted bone marrow-derived cells were engrafted into the olfactory epithelium and then had characteristics of olfactory neuron cells. However, the engraftment rate was far from a practical level. Granulocyte colony-stimulating factor (G-CSF) is known to mobilize stem cells from the bone marrow into the circulation. To assess the efficacy of G-CSF on engrafting transplanted bone marrow-derived cells into the olfactory epithelium, we performed the time window study of G-CSF administration. After C57BL/6 mice transplanted with bone marrow cells from GFP mice received selective damage of the olfactory epithelium by methimazole, G-CSF was administrated into the recipient mice at different time windows. A statistical analysis demonstrated that the early administration of G-CFS was appropriate to increase the engraftment rate of bone marrow-derived cells into the olfactory epithelium. Cells with double-immunostaining for GFP and OMP, GAP43 or cytokeratin were found in the olfactory epithelium of recipient mice. These results suggest that bone marrow-derived cells are engrafted as stem cells of the olfactory tissue and that the early administration of G-CSF is more effective to increase the engraftment rate of bone marrow-derived cell into the olfactory epithelium damaged by methimazole.
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PMID:The early administration of granulocyte colony-stimulating factor increases the engraftment of transplanted bone marrow-derived cells into the olfactory epithelium damaged by methimazole. 2050 66