Treatment with anti-CD18 monoclonal antibody slows the expansion of AAA in this experimental model. The associated inflammatory process at day 14, as indicated by monocyte infiltration, is reduced, but this effect may be opposed by the presence of hypertension. Further evaluation of the role of leukocytes and adhesion molecules in the expansion of AAA is warranted.

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Background and Purpose-The primary goal of these studies was to understand and investigate the capacity of perivascular nerves to influence the tone of human pial arteries and to compare them with other human cephalic arteries, the superficial temporal and middle meningeal. Methods-Responses to electrical activation of intramural nerves and related features of fresh segments of human cephalic arteries-the pial (PA; 478Ϯ34 m ID), middle meningeal (MMA; 540Ϯ41 m ID), and superficial temporal (STA; 639Ϯ49 m ID)-obtained from patients aged 15 to 82 years during surgical procedures were studied on a resistance artery myograph. Results-The PA segment responses to electrical nerve activation and to norepinephrine (NE; 10 Ϫ5 mol/L) were 1% and 21% of tissue maximum, respectively, compared with 6% and 34% for the MMA and 14% and 90% for the STA. Tissue maximum was defined as the force increase to 127 mmol/L KCl plus arginine vasopressin (1 m). All arteries dilated well to acetylcholine. Possible explanations for the PA marginal neurogenic responses were assessed. NE ED 50 was 5.4Ϯ2.2ϫ10Ϫ7 mol/L and did not vary with age or diameter. NE responsiveness did not increase in vessels with spontaneous or raised potassium-induced tone. Relaxation to isoproterenol was variable and propranolol did not increase the neurogenic response. Neither N G -monomethyl-L-arginine, N G -nitro-L-arginine methyl ester, endothelium removal, nor indomethacin consistently influenced the contractions to NE or neurogenic reactivity. The weak PA neurogenic response is in keeping with its poor innervation. As determined by catecholamine histofluorescence, innervation in the PA is sparse, with density increasing in the order PA, MMA, and STA. The incidence of nerve structures in the PA adventitio-medial junction was only 3% of those in the STA, and these were situated more than 3 m from the closest smooth muscle cell. Conclusions-We conclude that the weak neurogenic response of adult human pial artery reflects its poor innervation and responsiveness to NE, implying that these features are not important in the regulation of its diameter. (Stroke. 1998;29:212-221.)

Introduction Identifying fever can influence management of the emergency department (ED) patient, including diagnostic testing, treatment, and disposition. We set out to determine how well oral and tympanic membrane (TM) temperatures compared with rectal measurements.MethodsA convenience sample of consecutively adult ED patients had oral, TM, and rectal temperatures performed within several minutes of each other. Descriptive statistics, Bland–Altman agreement matrices with 95% confidence interval (CI), and measures of test performance, including sensitivity, specificity, predictive values, and interval likelihood ratios were performed.ResultsA total of 457 patients were enrolled with an average age of 64 years (standard deviation: 19 years). Mean temperatures were: oral (98.3°F), TM (99.6°F), and rectal (99.4°F). The mean difference in rectal and oral temperatures was 1.1°F, although there was considerable lack of agreement between oral and rectal temperatures, with the oral temperature as much as 2.91°F lower or 0.74°F higher than the rectal measurement (95% CI). Although the difference in mean temperature between right TM and rectal temperature was only 0.22°F, the right TM was lower than rectal by up to 1.61°F or greater by up to 2.05°F (95% CI). Test performance varied as the positive predictive value of the oral temperature was 97% and for tympanic temperature was 55% (relative to a rectal temperature of 100.4°F or higher). Comparative findings differed even at temperatures considered in the normal range; among patients with an oral temperature of 98.0 to 98.9, 38% (25/65) were found to have a rectal temperature of 100.4 or higher, while among patients with a TM of 98.0 to 98.9, only 7% (10/134) were found to have a rectal temperature of 100.4 or higher.ConclusionThe oral and tympanic temperature readings are not equivalent to rectal thermometry readings. Oral thermometry frequently underestimates the temperature relative to rectal readings, and TM values can either under- or overestimate the rectal temperature. The clinician needs to be aware of the varying relationship between oral, TM, and rectal temperatures when interpreting readings.

Responses of segments of basilar and middle cerebral arteries of eight human infants to activation of perivascular nerves and to vasoactive drugs were studied using a resistance artery myograph. The infants ages ranged from 23 wk of gestation to 34 postnatal days. Neurogenic vasoconstriction occurred in all segments and at 8 Hz was 12.7 +/- 3.5% (11%) of tissue maximum and was blocked by phentolamine (10(-6) M). There was no evidence of a neurogenic dilator response. Catecholamine histofluorescence was seen in nerves in the adventitia at all ages studied. Norepinephrine ED50 was 7.6 +/- 1.8 x 10(-7) M, and its maximum effect was 43.1 +/- 5.7% of tissue maximum. Both neural and norepinephrine responses were greater than those of the proximal parts of adult human middle cerebral arteries obtained postmortem and surgically removed adult human pial arteries. Electron microscopy demonstrated that neural density at the adventitiomedial junction in the infant vessels was greater than in the pial arteries. Constrictor responses to serotonin and prostaglandin F2 alpha were minimal in the two infants of 23 and 24 wk of gestation but were clearly present in the older infants. Histamine and acetylcholine were potent vasodilators. Indomethacin potentiated agonist-induced contraction. In a limited number of trials angiotensin II, neuropeptide Y, caused contraction and bradykinin, relaxation. It is concluded that there is a quantitative similarity between the studied responses of infant cerebral artery segments and human pial arteries of similar diameter. However, sympathetic nerves may potentially play a more important role in the regulation of cerebrovascular tone in the infant compared with the adult, and during the gestational period examined these vessels possess an indomethacin-sensitive system that buffers agonist tone.