Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0344232 (blurred vision)
 2,072 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A large number of reports have been devoted to the physiologic and toxic effects of methyl chloride, many of which are based on case histories involving occupational exposure. The detrimental actions of methyl chloride on the central and peripheral nervous systems are well established effects. It is a moderately severe narcotic and potentially severe nerve poison. Chronic intoxication is associated with damage to the central nervous system (CNS), kidneys, liver, bone marrow, cardiovascular system, respiratory system, and intestinal tract. The signs and symptoms range from the more severe medical dysfunctions such as cardiac irregularities, respiratory paralysis, nerve degeneration, and severe convulsions to the more subtle clinical observations such as CNS depression, nervousness and emotional instability, insomnia and anorexia, ataxia, blurred vision, light-headedness, nausea, dizziness, narcosis, and disorientation. The behavioral correlates of these and other neurotoxic effects of methyl chloride suggest that a gradual behavioral degradation occurs. Pharmacodynamic studies have shown the compound to be rapidly absorbed by the blood with most authors attributing the toxicity to an enzyme-catalyzed methylation reaction in the body. Despite the fact that several investigators have attempted to correlate such biological responses of methyl chloride with its toxicity, the present knowledge of the problem still lacks a detailed mechanism of action. Until such mechanisms are verified, adequate methods to assess subclinical neurological and behavioral changes must be effectively developed.
CRC Crit Rev Toxicol 1979 Nov
PMID:Behavioral, neurological, and toxic effects of methyl chloride: a review of the literature. 38 67

Tomographic cut is not synonymous to a roentgenogram of an anatomic cut. Blurring is inherent in the tomogram, and the edges do not appear as sharp as in the conventional roentgenogram. Part of the contrast is lost in tomography. Therefore, when tissue contrast is low, or when we intend to see an entire structure in one cut, zoneography is preferred. On the other hand, when many details are crowded in a small area and/or when the tissue contrast is high, a thin section tomography is indicated. Proper knowledge of the level of area of interest (focal plane) and proper spacing of the cuts decrease radiation and expenses. The Law of Tangent, namely, "The edge of a structure should be momentarily parallel to the beam at the focal plane, in order to show on the film," is an essential part of every tomographic study. The Law of Tangent applies equally to spheres and other curved surfaces. The effective tomographic angle is the angle described by the tube during exposure. The thickness of the cut depends on the effective tomographic angle. Prior viewing of conventional roentgenogram and proper knowledge of the mechanism of parasitic and phantom images help us to avoid mistaking these images as real structures.
CRC Crit Rev Clin Radiol Nucl Med 1976 Dec
PMID:Essential knowledge about pitfalls in tomography. 79 77