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Objectives:Sessile serrated polyps (SSPs) are suggested to be the precursors of 15–30% of all colorectal cancers (CRCs). Therefore, CRC screening modalities should also be designed to detect high-risk SSPs. We compared computed tomography colonography (CTC) with colonoscopy-based screening for the detection of high-risk SSPs in average-risk individuals.Methods:Data from a randomized controlled trial that compared CTC with colonoscopy for population screening were used for the analysis. Individuals diagnosed at CTC with a lesion ≥10 mm in size were referred for colonoscopy. Individuals with only 6–9 mm lesions were offered surveillance CTC. This surveillance CTC was followed by a colonoscopy when a lesion ≥6 mm was detected. Yield of both was accumulated to mimic current American College of Radiology CTC referral strategy (referral of individuals with any lesion ≥6 mm). Per participant detection of ≥1 high-risk (dysplastic and/or ≥10 mm) SSP was compared with colonoscopy using multiple logistic regression analysis.Results:In total, 8,844 individuals were invited to participate (in 2:1 allocation), of which 1,276 colonoscopy and 982 CTC invitees participated in the study. In the colonoscopy arm, 4.3% of individuals were diagnosed with ≥1 high-risk SSP, compared with 0.8% in the CTC arm (odds ratio (OR) 5.5; 95% confidence interval (CI) 2.6–11.6; P<0.001). In total, 3.1% of individuals in the colonoscopy arm were diagnosed with high-risk SSPs as most advanced lesion, compared with 0.4% in the CTC arm (OR 7.7; 95% CI 2.7–21.6; P<0.001). The current CTC strategy showed a marked lower detection for especially flat high-risk SSPs (17 vs. 0), high-risk SSP located in the proximal colon (32 vs. 1), and SSPs with dysplasia (30 vs. 1).Conclusions:In a randomized controlled setting, the detection rate of high-risk SSPs was significantly higher with colonoscopy than CTC. These results might have implications for CTC as a CRC modality for opportunistic screening in average-risk adults.

Background/Aims:: Lifestyle intervention is the only established therapy for non-alcoholic fatty liver disease (NAFLD). The optimal treatment schedule and predictors of response of this treatment have not been established in children. We aimed to evaluate the 2-year efficacy of an inpatient versus ambulatory intensive lifestyle intervention for treating NAFLD in children with severe obesity. Methods:: A cohort study of 51 severely obese non-diabetic children (mean age 14.7 (±2.4) years; BMI-z-score 3.5 (±0.5)) with liver steatosis were non-randomly allocated to inpatient treatment (2 or 6 months), ambulatory treatment or usual care. Proton Magnetic Resonance Spectroscopy determined liver steatosis and serum alanine aminotransferase (ALT) at 6 months were the primary outcome measures. Baseline variables were evaluated as predictors of treatment response. Results:: Liver steatosis had disappeared in 43, 29 and 22% and serum ALT normalized in 41, 33 and 6% at the end of 6 months in the inpatient, ambulatory or usual care treatment groups, respectively. Only the proportions of ALT normalization in inpatient and ambulatory treatment compared with usual care were significantly higher. Treatment effects of inpatient and ambulatory treatment were sustained at 1.5 years follow-up. No baseline characteristic, including PNPLA3 polymorphism or leptin, was consistently predictive for treatment response. Conclusions:: A 6-month intensive inpatient and ambulatory lifestyle treatment in children with severe obesity reverses NAFLD in a minority of patients. This study suggests that inpatient compared with ambulatory intensive treatment does not importantly increase treatment success. Further efforts to optimize and individualize lifestyle interventions and additional treatments options are needed particular for children with severe obesity resistant to conventional lifestyle interventions.

Background & Aims: To date, computed tomographic (CT) colonography has been compared with an imperfect test, colonoscopy, and has been mainly assessed in patients with positive screening test results or symptoms. Therefore, the available data may not apply to screening of patients with a personal or family history of colorectal polyps or cancer (increased risk). We prospectively investigated the ability of CT colonography to identify individuals with large (>=10 mm) colorectal polyps in consecutive patients at increased risk for colorectal cancer. Methods: A total of 249 consecutive patients at increased risk for colorectal cancer underwent CT colonography before colonoscopy. Two reviewers interpreted CT colonography examinations independently. Sensitivity, specificity, and predictive values were determined after meticulous matching of CT colonography with colonoscopy. Unexplained large false-positive findings were verified with a second-look colonoscopy. Results: In total, 31 patients (12%) had 48 large polyps at colonoscopy. This included 8 patients with 8 large polyps that were overlooked initially and detected at the second-look colonoscopy. In 6 of 8 patients, the missed polyp was the only large lesion. With CT colonography, 84% of patients (26/31) with large polyp(s) were identified, paired for a specificity of 92% (200-201/218). Positive and negative predictive values were 59%-60% (26/43-44) and 98% (200-201/205-206), respectively. CT colonography detected 75%-77% (36-37/48) of large polyps, with 9 of the missed lesions being flat. Conclusions: CT colonography and colonoscopy have a similar ability to identify individuals with large polyps in patients at increased risk for colorectal cancer. The large proportion of missed flat lesions warrants further study.

This contribution focuses on the way in which employees and managers perceive themselves and each other. Based on two PhD-projects, one in which differences between self-ratings and supervisor ratings have been studied, and one in which the focus was the differences between team leaders' self-perception and the team members' perception, it was concluded that supervisors and employees have a different view on the competencies and behavior of one another. Some explanations for these results are given. Also, implications for competence development and appraisal of employees and managers will be described.

The present study was designed to investigate the effect of progesterone on the coronary circulation and to determine the mechanisms involved. In pigs anaesthetized with sodium pentobarbitone, changes in left circumflex or anterior descending coronary blood flow caused by intravenous infusion of progesterone at constant heart rate and arterial blood pressure were assessed using an electromagnetic flowmeter. In 14 pigs, infusion of 1 mg h-1 of progesterone caused an increase in coronary blood flow without affecting left ventricular dP/dtmax (rate of change of left ventricular systolic pressure) and filling pressures of the heart. In a further four pigs, this vasodilatory coronary effect was enhanced by graded increases in the dose of the hormone of between 1, 2 and 3 mg h-1. The mechanisms of the above response were studied in the 14 pigs by repeating the experiment after haemodynamic variables had returned to the control values observed before infusion. In six pigs, blockade of muscarinic cholinoceptors and adrenoceptors with atropine, propranolol and phentolamine did not affect the coronary vasodilatation caused by progesterone. In the remaining eight pigs, this response was abolished by intracoronary injection of Nω-nitro-L-arginine methyl ester (L-NAME) even when performed after reversing the increase in arterial blood pressure and coronary vascular resistance caused by L-NAME with continuous intravenous infusion of papaverine. The present study showed that intravenous infusion of progesterone primarily caused coronary vasodilatation. The mechanism of this response was shown to involve the endothelial release of nitric oxide. Experimental Physiology (2001) 86.1, 101-108.

The present study was designed to investigate the effect of progesterone on the coronary circulation and to determine the mechanisms involved. In pigs anaesthetized with sodium pentobarbitone, changes in left circumflex or anterior descending coronary blood flow caused by intravenous infusion of progesterone at constant heart rate and arterial blood pressure were assessed using an electromagnetic flowmeter. In 14 pigs, infusion of 1 mg h−1of progesterone caused an increase in coronary blood flow without affecting left ventricular dP/dtmax(rate of change of left ventricular systolic pressure) and filling pressures of the heart. In a further four pigs, this vasodilatory coronary effect was enhanced by graded increases in the dose of the hormone of between 1, 2 and 3 mg h−1. The mechanisms of the above response were studied in the 14 pigs by repeating the experiment after haemodynamic variables had returned to the control values observed before infusion. In six pigs, blockade of muscarinic cholinoceptors and adrenoceptors with atropine, propranolol and phentolamine did not affect the coronary vasodilatation caused by progesterone. In the remaining eight pigs, this response was abolished by intracoronary injection of Nω‐nitro‐L‐arginine methyl ester (L‐NAME) even when performed after reversing the increase in arterial blood pressure and coronary vascular resistance caused by L‐NAME with continuous intravenous infusion of papaverine. The present study showed that intravenous infusion of progesterone primarily caused coronary vasodilatation. The mechanism of this response was shown to involve the endothelial release of nitric oxide.

The purpose of the study was to evaluate CT criteria for venous invasion in patients with potentially resectable carcinoma of the pancreatic head, with surgical and histopathological correlation. In 113 patients evaluated with spiral CT for suspected pancreatic head carcinoma, several CT criteria for venous invasion were scored prospectively for the portal vein (PV) and the superior mesenteric vein (SMV): length of tumour contact with PV/SMV (0 mm, < 5 mm, > 5 mm); circumferential involvement of the vein (0 degree, 0-90 degrees, 90-180 degrees, > 180 degrees); degree of stenosis; irregularity of the vessel margin; and tumour convexity towards vessel. 65 patients underwent surgery. Pancreatic head carcinoma was proven and pathology of the vascular margin was obtained in 50 of these patients. CT findings for single and combined criteria were correlated with pathology in these 50 patients, 30 of whom showed venous ingrowth. Invasion was found in all cases with SMV narrowing (n = 7), PV contour involvement > 90 degrees (n = 6), PV narrowing (n = 5) and PV wall irregularity (n = 3). The vascular ingrowth rate was 88% (15/17) for tumour concavity towards the PV or SMV. Poor predictors of ingrowth were length of tumour contact with PV > 5 mm (78% ingrowth, 14/18) and contour involvement of the SMV > 90 degrees (83% ingrowth, 10/12). Absence of vascular ingrowth could not be predicted in 100%. In conclusion, CT criteria can predict a high risk of invasion in potentially resectable tumours. Narrowing of the SMV and the PV seems the most reliable criterion, as well as circumferential involvement of the PV > 90 degrees. The best combination of criteria was tumour concavity with circumferential involvement > 90 degrees (sensitivity 60% and positive predictive value 90%).

Fecal incontinence is a major medical and social problem. The most frequent cause is a pathologic condition of the anal sphincter. Endoanal magnetic resonance (MR) imaging allows detailed visualization of the normal anatomy and pathologic conditions of the anal sphincter. The hyperintense internal sphincter appears as a continuation of the smooth muscle of the rectum; the hypointense external sphincter surrounds the lower part of the internal sphincter. A sphincteric defect is seen as a discontinuity of the muscle ring. Scarring appears as a hypointense deformation of the normal pattern of the muscle layer. Two external sphincteric patterns may be misdiagnosed as defects: a posterior discontinuity (often seen in young male patients) and an anterior discontinuity (often seen in female patients). Atrophy of the external sphincter is easily detected on coronal MR images by comparing the thicknesses of all anal muscles. Endoanal MR imaging is superior to endoanal ultrasonography because of the multiplanar capability and higher inherent contrast resolution of the former. Use of endoanal MR imaging may lead to better selection of candidates for surgery and therefore better surgical results. Endoanal MR imaging is the most accurate technique for detection and characterization of sphincteric lesions and planning of optimal therapy.

Abstract: The anatomy of the female pelvic floor and urethra is complex. With the introduction of MRI, the discussion about the normal anatomy of this area has not diminished. The use of a body coil may be contributary to this. In the present study images obtained with an endovaginal coil are compared with those of a quadrature body coil series to study the possible advantages of endovaginal imaging. Axial and radial T2-w TSE images at a 1.0-T machine were obtained in seven healthy volunteers. The pelvic floor structures as well as the levator ani muscle and the urogenital diaphragm are excellently demonstrated with the endovaginal coil. Also, the urethrovaginal sphincter could be recognized in six volunteers, but only in three with the body coil. In six volunteers a new ligamentous structure, the urethropelvic sling, connecting the urethra to the levator ani muscle and contributing to the supporting mechanism of the urethra is shown with the endovaginal coil. The zonal anatomy of the urethra is excellently shown with the endovaginal coil. The urethral length could only be accurately measured with this coil and ranged from 3.1 to 3.6 cm. Compared with the body coil, endovaginal MRI is excellent in demonstrating the anatomy of the pelvic floor and urethra.

1. The aortic arch and both carotid sinuses were vascularly isolated and perfused. A hind limb was vascularly isolated and blood was pumped at constant flows into the femoral artery and the central end of a superficial metatarsal vein. 2. Large increases in aortic arch pressure resulted in decreases in arterial blood pressure, heart rate and femoral arterial perfusion pressure. The average response of the vein was a decrease of 11% in the pressure gradient between the perfused vein and the femoral vein. Similar responses were obtained when carotid sinus pressure was increased. 3. Crushing or cooling the lumbar sympathetic trunk caused responsed similar to those induced by increasing baroreceptor perfusion pressure. Stimulation at 1 HZ resulted in venous responses four times as great as the average reflex response, whereas frequencies of 2‐5 Hz were required to produce changes in arterial resistance as great as those induced reflexly. 4. These experiments indicate, that although the large superficial veins of the dog's hind limb participate in the baroreceptor reflexes, the activities in the nerves supplying arterioles and veins must have been different.

The mutual-diffusion coefficients, D12, of n-hexane, n-heptane, and n-octane in chloroform were modeled using equilibrium molecular-dynamics (MD) simulations of simple Lennard-Jones (LJ) fluids. Pure-component LJ parameters were obtained by comparison of simulations to experimental self-diffusion coefficients. While values of “effective” LJ parameters are not expected to simulate accurately diverse thermophysical properties over a wide range of conditions, it was recently shown that effective parameters obtained from pure self-diffusion coefficients can accurately model mutual diffusion in ideal, liquid mixtures. In this work, similar simulations are used to model diffusion in nonideal mixtures. The same combining rules used in the previous study for the cross-interaction parameters were found to be adequate to represent the composition dependence of D12. The effect of alkane chain length on D12 is also correctly predicted by the simulations. A commonly used assumption in empirical correlations of D12, that its kinetic portion is a simple, compositional average of the intradiffusion coefficients, is inconsistent with the simulation results. In fact, the value of the kinetic portion of D12 was often outside the range of values bracketed by the two intradiffusion coefficients for the nonideal system modeled here.

Abstract.: Twenty consecutive patients with the clinical suspicion of a perianal fistula were studied to define the optimal and time-efficient imaging planes for endoanal MRI in the identification and classification of perianal fistulas. The duration of each part of the MR procedure was recorded in all patients. Off-axis axial (A), coronal (C), sagittal (S) and radial (R) T2-weighted sequences were performed in all patients. Sets of images and combinations of images (A; R; CS; AR; ACS; ARCS) without patient data were reviewed in masked fashion and independently with a 2-month interval between each set. The reader was masked to the results of previous readings. The findings were compared with the surgical findings. The number of correctly identified and classified fistula and the sensitivity and specificity were determined. Twenty fistulas were present at surgery: 14 transsphincteric fistulas and six intersphincteric fistulas. Eighteen fistulas were correctly identified with the radial (R) and combined coronal sagittal (CS) sequences. In all other sequences or combinations of sequences all 20 fistulas were identified. Classification was correct with A in 16 patients, with R in 15, with CS in 15, with AR in 18, with ACS in 17 and with ARCS in 18. The sensitivity and specificity were optimal using AR or ARCS (0.86 and 1 respectively). The optimal and most time-efficient imaging protocol for endoanal MRI of perianal fistulas thus comprises the axial and radial imaging planes.

1. Carbon dioxide titration curves were determined in vivo in dog and man at various degrees of acute non-respiratory acidaemia and alkalaemia. 2. The slope of the CO2 titration curve (?log Pco2/?pH) was found to increase with the severity of the acute non-respiratory acidaemia. In states of acute non-respiratory alkalaemia the slope (?log Pco2/?pH) tended towards unity. 3. A simple scheme based on the CO2 titration curves determined in vivo has been proposed for the assessment of acute acid-base disturbances in man. 4. Carbon dioxide titration curves were also determined in vivo in patients with chronic respiratory and non-respiratory acidaemia and it was found that these curves were not significantly different from those obtained in states of acute acid-base disturbances. It is therefore suggested that the scheme described in this paper is applicable to all acid-base disturbances.

1. Nifedipine is used in patients with stable angina of effort and any resulting change in symptoms is attributed to several effects of nifedipine. However, there have been indications in such patients that one effect of nifedipine could be an increase in the severity of myocardial ischaemia, and the present report involves a trial the results of which could explain this effect. 2. In the present trial, the effect of nifedipine on myocardial ischaemia was assessed by using the maximal ST/heart rate slope. This slope was used as an index of myocardial ischaemia because, in our hands in patients with angina, an increase or a decrease in the value of the slope respectively indicated an increase or a decrease in the severity of myocardial ischaemia as assessed by coronary arteriography. 3. The maximal ST/heart rate slope was obtained at least twice in each of 23 patients with stable angina, with and without nifedipine; two patients were examined twice and three other patients were examined after an increased dose. Nifedipine resulted in an increase in the slope in 24 of the 28 comparisons, no change in three and a decrease in one comparison; there was a statistically significant (P < 0.005; n = 28; paired t-test) increase in the maximal ST/heart rate slope. A further increase in the slope was obtained by increasing the dose of nifedipine in two out of three patients. 4. The increase in the maximal ST/heart rate slope occurred in the absence of any effect of nifedipine on the initial level of the ST segment. 5. It is concluded that nifedipine therapy in the patients with stable angina caused increases in the maximal ST/heart rate slope, suggesting an increase in the severity of myocardial ischaemia.

The effecacy of monensin, a fermentation product of Streptomyces cinnamonensis was evaluated and compared with four commonly used anticoccidial agents in the control of naturally occurring coccidial infection of broiler chickens. Results are reported from 25 floor pen trials, involving 90,678 birds allotted to 289 replicates, at 11 locations in England, France, Holland and Spain.Untreated control groups of birds were included where possible to measure the degree of exposure to infection. Parameters measured were mortality from coccidiosis, final live body weight, feed conversion efficiency and the incidence of coccidial lesions scored at two periods of time during each trial.Results were analysed using a computer programme which permitted the pooling of data from several trials which provided adjusted treatment means and analyses of variance of treatment differences. Analysis of data from all trials showed that in comparison to untreated controls the inclusion of 0.012% monensin in the feed gave statistically significant improvements in final body weight, feed conversion efficiency and control of coccidial lesions. The other anticoccidial agents tested showed similar improvements in body weight but smaller differences in feed efficiency and reduction of lesions.

Subjects carried out a paired comparison experiment in which they were asked to make a preference judgement between a computer facsimile of an original Mondrian painting, and a modified version of the same picture in which the proportional relations of the compositional lines had been modified by a relatively small amount. Subjects were significantly better than chance expectations in their preference for the original Mondrians, suggesting that these paintings may encapsulate some universal principle of compositional order which can be detected by subjects.

A method is described for the isolation and purification of bound coumarin from seeds of Melilotus alba. Synthetic coumarinic acid β-glucoside has been prepared and its properties compared with those of bound coumarin. The results of these experiments confirm that bound coumarin and coumarinic acid β-glucoside are identical.

A method is described for the isolation and purification of bound coumarin from seeds of Melilotus alba. Synthetic coumarinic acid β-glucoside has been prepared and its properties compared with those of bound coumarin. The results of these experiments confirm that bound coumarin and coumarinic acid β-glucoside are identical.

1. Simultaneous CO2 titration curves of arterial and mixed venous blood were determined in both dog and man in vivo. 2. The slopes of the CO2 titration curves of mixed venous blood were significantly less than those of the corresponding arterial curves. 3. The non-respiratory pH values of the CO2 titration curves of mixed venous blood were significantly greater than those of the corresponding arterial curves. 4. The theoretical explanations of these differences have been discussed.

1. CO2 titration curves in vivo were determined at various degrees of acute non-respiratory acidaemia in man. 2. The slope of the CO2 titration curve was found to increase as the severity of the acute non-respiratory acidaemia increased. 3. A simple scheme based on the CO2 titration curves in vivo has been proposed for the assessment of acute acidaemia in man.

In this paper a complete mathematical solution of the problem of the buckling with large deflections of a thin circular plate under uniform radial pressure is given, assuming radial symmetry. Buckling takes place as soon as the prescribed thrust pe at the edge reaches a certain critical value pE. Thin plates do not, however, fail if the thrust pe is increased beyond pE. It is of importance, then, to determine the stresses when the ratio Λ = pe/pE becomes greater than unity. This problem, which is a nonlinear one, is solved by two methods for finite values of Λ; also an asymptotic solution is given for the limit state when Λ tends to infinity. The most notable single result is that the membrane stresses for large values of Λ become tensions in the interior of the plate and change abruptly to compressions in a narrow “boundary layer” at the edge of the plate. Curves showing the behavior of the deflection and the stresses are given for a series of values of Λ. Such curves show clearly, in particular, that the limit state is approached quite closely for relatively small values of Λ, i.e., Λ > 5. In closing, the authors discuss the relation between their results and von Kármán’s theory of effective width for the buckling of rectangular plates.

The role of felodipine, a new calcium antagonist, in monotherapy for mild and moderate hypertension was investigated in a placebo-controlled double-blind study of 109 patients from 13 centres. The patients were randomised in a double-blind fashion to receive felodipine, 2.5 mg b.i.d. (32 patients), 5 mg b.i.d. (30 patients), 10 mg b.i.d. (24 patients), or placebo (23 patients). Two hours after the first tablet was administered, there was a reduction in systolic and diastolic blood pressure, both supine (p < 0.05) and standing (p < 0.001), that was significantly correlated with dose. Three and 8 weeks later, 2 h after dosage, this correlation was still apparent in both supine and standing blood pressure (p < 0.001). One week after randomisation, at 12 hours after administration there was a significant correlation with dose in the standing systolic (p < 0.05) and diastolic (p < 0.01) blood pressure. After 8 weeks therapy, a significant correlation with dose occurred in both supine and standing systolic (p < 0.05) and diastolic (p < 0.01) blood pressure 12 h after therapy. The proportion of patients completing the study who achieved a supine diastolic blood pressure of 90 mm Hg or less after 8 weeks therapy at 2 h after dosage was 9 on placebo, 67 on felodipine 2.5 mg b.i.d., 57 on felodipine 5 mg b.i.d., and 92 on felodipine 10 mg b.i.d. Felodipine was generally well tolerated although 10 patients on the highest dose withdrew due to adverse experiences. Plasma felodipine levels were significantly correlated with dose. Felodipine monotherapy significantly reduces blood pressure in mild and moderate hypertension, and doses of 2.5 mg b.i.d. and 5 mg b.i.d., can be recommended for initial treatment of this category of patients.

The nuclear magnetic moment of the ground state of 57Cu(Iπ= 3/2-, T1/2= 196.3 ms) has been measured to be |μ(57Cu)| = (2.00 ±0.05) μNusing the β-NMR technique. Together with the known magnetic moment of the mirror partner 57Ni, the spin expectation value was extracted as $\langle\sum\sigma_z\rangle$= -0.78 ± 0.13. Discrepancy between present results and shell model calculations in the full fp shell implies significant shell breaking at 56Ni with the neutron number N = 28.

Abstract.: The nuclear magnetic moment of the ground state of 57Cu(Iπ = 3/2-, T1/2 = 196.3 ms) has been measured to be |μ(57Cu)| = (2.00 ±0.05) μN using the β-NMR technique. Together with the known magnetic moment of the mirror partner 57Ni, the spin expectation value was extracted as $\langle\sum\sigma_z\rangle$ = -0.78 ± 0.13. Discrepancy between present results and shell model calculations in the full fp shell implies significant shell breaking at 56Ni with the neutron number N = 28.

The nuclear magnetic moment of the ground state of 57Cu(I?= 3/2-, T1/2= 196.3 ms) has been measured to be |?(57Cu)| = (2.00 ?0.05) ?Nusing the ?-NMR technique. Together with the known magnetic moment of the mirror partner 57Ni, the spin expectation value was extracted as [Formula: see text]?[Formula: see text] = -0.78 ? 0.13. Discrepancy between present results and shell model calculations in the full fp shell implies significant shell breaking at 56Ni with the neutron number N = 28.

1. The adequacy of the control of essential hypertension during exercise was studied in patients whose resting blood pressure had been controlled for 1 year with either metoprolol or methyldopa. 2. Systolic blood pressure increased with exercise in both groups, the increase being significantly less in the metoprolol group than in the methyldopa group.

To the Editor.—Methemoglobin levels are maintained in humans at less than 1%. Elevation in this value can be manifested by peripheral cyanosis. Congenital and acquired causes exist. This article reports a case of methemoglobinemia secondary to the use of sulfamethoxazole and trimethoprim.Report of a Case.—A 22-year-old woman was referred to us from the Urology Department for evaluation of cyanosis of one day's duration. She had been receiving sulfamethoxazole and trimethoprim therapy for eight days for a urinary tract infection. She was taking no other medications. Physical examination disclosed peripheral cyanosis. Laboratory examination disclosed a hemoglobin level of 13.8 g/mL, with an adult hemoglobin-A electrophoretic pattern. Arterial blood gases on room air showed a Po2, Pco2, and pH of 96 mm Hg, 34 mm Hg, and 7.30, respectively. However, her methemoglobin level was elevated at 18.3%. After the patient was instructed to discontinue use of all