Long-term soil accumulation of chromium, copper, and arsenic adjacent to preservative-treated wood.
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Arsenates↗
Biomedical subjects
S Lebow
Publications and source records attributed to S Lebow.
Prediction of carotid disease by ultrasound and digital subtraction angiography.
Ultrasound (US) technology (B-mode real-time imaging and Doppler signal analysis) and digital subtraction angiography (DSAV) were prospectively compared in 90 consecutive patients. Twenty-four endarterectomy specimens became available. The DSAV was uninterpretable in 9.4% of vessels and US, in 8.3%. Estimation of degree of stenosis by both modalities agreed well with endarterectomy specimens. Neither predicted the presence or absence of ulceration accurately. Not considering occlusions (where DSAV is probably more accurate), no clear superiority as a screening test compared against a common standard was demonstrated for either. In all 148 vessels with adequate studies by both, the technologies agreed in categorizing stenosis (less than or equal to 50% v greater than 50% diameter stenosis) in 89%. Correlation was poor for occlusions and ulceration. If DSAV were definitive, US would be an effective screen for surgically relevant stenosis with a negative predictive value of 95%.
Aged↗
Acute multiple sclerosis with contrast-enhancing plaques.
In a case of clinically fulminant multiple sclerosis (MS), contrast-enhancing lesions were visible by computerized axial tomography (CT). The patient died less than three weeks after the study, making neuropathologic correlation possible. It appears that areas of contrast enhancement correlate in acute MS with early demyelinative lesions, and enhancement is related to breakdown of the blood-brain barrier. That such a disturbance is important in the pathogenesis of demyelination in MS has been suggested by other data as well. The characteristic CT findings of MS must therefore include enhancing lesions that reflect disease activity and that may be the only CT abnormality.
Acute Disease↗
The effects of the morphine analogue levorphanol on leukocytes. Metabolic effects at rest and during phagocytosis.
Studies on bacteria have suggested that morphine-like drugs have effects on the cell membrane. To determine the effect of this class of drugs on a mammalian cell, we selected the rabbit peritoneal exudate granulocyte, which undergoes striking membrane changes during phagocytosis. We examined the effect in vitro of the morphine analogue, levorphanol on phagocytosis and metabolism by granulocytes incubated with and without polystyrene particles or live Escherichia coli. Levorphanol (1 or 2 mmoles/liter) decreased: (a) acylation of lysolecithin or lysophosphatidylethanolamine in the medium (which is stimulated about two-fold during phagocytosis) both at rest (40%) and during phagocytosis (60%); (b) uptake of latex particles and Escherichia coli, as judged by electron microscopy; (c) killing of live Escherichia coli (10-fold); (d) (14)CO(2) production from glucose-1-(14)C during phagocytosis by at least 80%; (e) K(+) content of granulocytes (35%); (f) oxidation of linoleate-1-(14)C by 50%, and its incorporation into triglyceride by more than 80%. However, levorphanol stimulated 2 to 3-fold the incorporation of linoleate-1-(14)C or palmitate-1-(14)C into several phospholipids. Glucose uptake, lactate production, and adenosine triphosphate (ATP) content are not affected by the drug. Thus, levorphanol does not appear to exert its effects through generalized metabolic suppression. Removal of levorphanol by twice resuspending the granulocytes completely reverses all inhibition. In line with observations on bacteria, it appears that the complex effects of levorphanol on granulocytes may be due at least in part to an effect on the cell membrane.
Animals↗