The International Society of Radiology.
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Canada↗
Biomedical subjects
D B Fraser
Publications and source records attributed to D B Fraser.
Reversed phase ion-pair liquid chromatographic determination of nicotine in commercial tobacco products. 1. Moist snuff.
The official methods for the determination of nicotine in commercial tobacco products (AOAC, CORESTA) are based on approaches that are not selective for nicotine (colorimetric measurement, steam distillation, perchloric acid titration), and the availability of published methods based on state-of-the-art chromatographic methods is limited. Reversed phase ion-pair liquid chromatography has been established as a viable alternative for the analysis of basic analytes. A reversed phase ion-pair liquid chromatographic method for the determination of nicotine in commercial tobacco products was developed and optimized in separate experiments (Ciolino, L. A.; Turner, J. A.; McCauley, H. A.; Smallwood, A. W.; Yi, T. Y. J. Chromatogr. 1999a, 852 (2), 451-463). An extensive within-laboratory performance study of the optimized method was subsequently conducted, and results are presented here for the determination of nicotine in commercial moist snuff. Results for the determination of nicotine in commercial cigarettes are presented in a subsequent paper.
Chromatography, Liquid↗
Reversed phase ion-pair liquid chromatographic determination of nicotine in commercial tobacco products. 2. Cigarettes.
A reversed phase ion-pair liquid chromatographic method for the determination of nicotine in commercial tobacco products was previously developed and optimized (Ciolino, L. A.; Turner, J. A.; McCauley, H. A.; Smallwood, A. W.; Yi, T. Y. J. Chromatogr. 1999a, 852 (2), 451-463) and provided reliable results for the determination of nicotine in commercial moist snuff (Ciolino, L. A.; McCauley, H. A.; Fraser, D. B.; Barnett, D. Y.; Yi, T. Y.; Turner, J. A. J. Agric. Food Chem. 1999b, 47, 3706-3712). The method uses an aqueous-based sample extraction and provides rapid separation of nicotine from the minor tobacco alkaloids and other commercial tobacco components. In the present work, the method is evaluated for the determination of nicotine in commercial cigarettes and compared to both an official AOAC method for total alkaloids in tobacco (AOAC, AOAC Official Methods of Analysis of AOAC International, 16th ed.; AOAC International: Gaithersburg, MD, 1995; pp 30-31), and a published GC method (Lyerly, L. A.; Greene, G. H. Beitr. Tabakforsch. 1976, 8 (6), 359-361). Good agreement was obtained between the ion-pair LC method and the GC method with relative differences in determined nicotine contents of 0.6 to 5% for a series of commercial and reference cigarettes.
Chromatography, Gas↗
Medical education and the RSNA.
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Education, Medical, Continuing↗
Constructing a curriculum vitae: the radiologist's resume.
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Humans↗
The RSNA Electronic Journal: RSNA EJ.
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Computer Communication Networks↗
Ultrasonography-directed native renal biopsy: comparison of an automated biopsy device with a needle system.
The authors compared the performance of an automated biopsy device with a large-bore cutting needle system in ultrasonography-guided native renal biopsy. They retrospectively analysed 52 biopsy specimens from 50 adults with diffuse renal parenchymal disease. Twenty-six consecutive biopsy samples had been obtained manually with a 14-gauge needle (Tru-Cut, Travenol Laboratories, Deerfield, Ill.); a second set of 26 samples had been obtained with a biopsy gun (Bard Biopty, Radiplast, Uppsala, Sweden) fitted with a 14-gauge needle of similar design. The systems were compared in terms of the specimens obtained (the adequacy and the quality of tissue, the number of intact glomeruli and the presence of artifacts) and the incidence of biopsy-related complications. Biopsy specimens obtained with the biopsy gun were judged qualitatively as well as quantitatively superior; they contained an average of 17.6 intact glomeruli, whereas only 11.5 intact glomeruli were retrieved with the needle system. Although the incidence of minor complications was lower after biopsy with the automated gun than after use of the needle system (8% and 15% respectively), two major complications were observed after gun biopsy and none after needle biopsy. The results reported here indicate that for native renal biopsy the Biopty gun delivers a higher-quality tissue core with a lower frequency of minor complications, but not of major complications, than the Tru-Cut needle system.
Adult↗
Pneumatosis coli: is there a relationship with sigmoid colon redundancy?
Pneumatosis coli (PC) is a process characterized by gas-filled cysts in the wall of the large intestine. The barium enema examinations of 14 patients with idiopathic PC were assessed: 93% involved the sigmoid colon, and 84% of patients with sigmoid pneumatosis had sigmoid colon redundancy in comparison to 14% of the control population (p less than 0.001). It is proposed that the sigmoid cysts result in redundancy by affecting the mesentery and colon length. This redundancy may account for the increased risk of sigmoid volvulus in this condition.
Barium Sulfate↗
Variations in fluoroscopic and spot film techniques during extracorporeal shock wave lithotripsy.
The radiation techniques of different operators who performed extracorporeal shock wave lithotripsy of the kidney were evaluated retrospectively. The study was limited to 9 operators who each performed more than 100 procedures on the Dornier lithotriptor. The average fluoroscopic time and number of video spot films per procedure for all operators were 4.1 minutes and 6.5, respectively. However, the average fluoroscopic time per operator varied from 1.4 to 7.6 minutes and the average number of video spot films per operator varied from 3 to 13. The results illustrate the need for some operators to reduce fluoroscopic time and video spot filming.
Fluoroscopy↗
Extracorporeal shock-wave lithotripsy in the management of bile duct stones.
Extracorporeal shock-wave lithotripsy (ESWL) was performed in 16 patients with bile duct stones. Dornier HM3 water-bath equipment (Dornier Medical Systems, Marietta, GA) was used in all procedures. All patients had either a T-tube or a nasobiliary, cholecystostomy, or transhepatic biliary drainage tube in place at the time of the lithotripsy. In 12 patients, the indication for ESWL was the failure of or anticipated difficulty with basket extraction of the stones, either via a T-tube tract or by means of endoscopic sphincterotomy. In the other four patients, ESWL was performed immediately after retained stones were found on a postoperative cholangiogram, even though no difficulty was anticipated in removing the stones by means of basket extraction. In 15 (94%) of the 16 patients, the stones were successfully fragmented. The fragments passed spontaneously in nine patients but had to be removed by basket in five patients. In one patient, the fragments could not be extracted by basket. The number of ESWL shocks used in a single session ranged from 525 to 3200. Three patients had two ESWL sessions. No significant complications were observed. ESWL is a successful method for the management of patients with bile duct stones when used in conjunction with other nonsurgical techniques. It was also the only treatment required in 56% of our patients.
Adult↗
Pain in peripheral arteriography: an assessment of conventional versus ionic and non-ionic low-osmolality contrast agents.
Two low-osmolality contrast agents, ioxaglate meglumine/sodium and iohexol were compared with diatrizoate meglumine/sodium in a controlled double blind study of 126 patients undergoing arteriography for peripheral vascular disease to determine which caused the least pain. Discomfort was assessed by means of a visual analog scale rating pain from 0 to 100. Average values for pain were 39 +/- 27 for diatrizoate, 14 +/- 15 for ioxaglate and 21 +/- 22 for iohexol. We found that both low-osmolality agents caused significantly less pain in peripheral arteriography than the traditional agent. The p values were p less than 0.0005 for ioxaglate and p less than 0.005 for iohexol versus diatrizoate. In addition, ioxaglate was found to cause significantly less pain than iohexol (p less than 0.05) in this patient group.
Adult↗
Therapeutic embolization of the hepatic artery.
We have performed therapeutic embolization of the hepatic artery and its branches in 15 patients, 14 with metastatic neoplasm and one with postoperative hepatobiliary hemorrhage. In the latter patient, bleeding ceased on embolization of the right hepatic artery and did not recur. The median survival time of the 14 patients who had hepatic embolization was six months. The mean survival time in our three patients with metastatic gastric leiomyosarcoma was 24 months, whereas our five patients with metastases from carcinoma of the colon had a mean survival time of only five months. On the basis of this experience we conclude that hepatic artery embolization is advisable in patients with hormonal effects of metastatic disease and in patients with massive hepatomegaly related to metastases from gastric leiomyosarcomas, and may be indicated in patients with hepatic artery hemorrhage.
Adult↗
Effect of upper airway carbon dioxide on ventilation and blood gases in the awake pony.
Carbon dioxide concentrations were increased during expiration in the upper one-half of the trachea, pharynx, and nasal sinuses to determine if elevation of upper airway CO2 would alter breathing or arterial blood gases in the awake pony. Carbon dioxide (100%) was injected into the midcervical trachea via a chronically implanted transcutaneous cannula during the first part of the animal's expiration. This maneuver elevated upper airway expiratory CO2 concentrations but prevented any exogenous CO2 from entering the lung and being absorbed into the arterial blood. Twelve experiments were performed on six ponies in which upper airway CO2 was elevated 2, 4, and 6% above the normal expired CO2 concentrations. Tidal volume increased in a dose dependent manner during upper airway CO2 exposure, but total ventilation was unchanged from base-line measurements made while the animal breathed room air. Arterial Po2 also increased during upper airway CO2 administration, reaching a mean value 6 Torr (1 Torr = 133.322 Pa) greater than the base-line values at the +6% CO2 exposure. We conclude that upper airway CO2 exposure alters breathing pattern slightly (increases tidal volume) and increases arterial PO2 in the awake pony.
Animals↗
The radiographic features of epidemic and sporadic Q fever pneumonia.
Radiographic dissimilarities exist between the chest radiographs of patients with epidemic and sporadically-occurring Q fever pneumonia. Chest radiographs of 25 patients with Q fever pneumonia were retrospectively assessed, and demonstrated previously unreported differences between these two broad groups. Differing strains of Coxiella burnetii, or varying doses of the pathogen, are postulated as the pathogenetic mechanisms for the observed discrepant findings.
Adult↗
Cerebrovascular response to acute decreases in arterial PO2.
The purpose of these studies was to examine the time course of the cerebrovascular response to acute hypoxia in unanesthetized ponies. An electromagnetic flow transducer chronically placed on the internal carotid artery of the pony allowed continuous recording of internal carotid artery blood flow (ICBF) which has been shown to be representative of cerebral blood flow (CBF). The ponies were subjected to three levels of acute isocapnic hypoxia (PaO2 = 62, 44, and 39 mm Hg for hypoxia level I, II, and III, respectively), and the temporal and steady-state cerebrovascular response was examined. ICBF increased significantly at all three hypoxia levels (8, 25, and 40% at hypoxia I, II, and III, respectively). This increase was rapid in the two most severe levels of hypoxia, beginning within 45 s, and was complete within 90 s. The increase lagged behind the reduction in PaO2 by 24-28 s. During the very mild level of hypoxia (I), no such rapid increase in flow was observed; rather, the increase occurred only after 5 min of hypoxia. Microsphere (15 microns diameter) measurements from six ponies during the most severe level of hypoxia (III) demonstrated that CBF increased 38%. Noncerebral tissues known to be vascularly connected to the circle of Willis, and thus capable of receiving blood flow via the internal carotid artery, either did not change or increased so slightly during hypoxia that their effect on ICBF was minimal.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Digital subtraction arteriography (DSA) in re-evaluation of angioplasties.
Digital subtraction arteriography (DSA) permits accurate, objective, and relatively pain-free evaluation of the morphology of angioplasty sites. During 1982, we performed DSA on 74 patients who had had 96 angioplasties over the previous three and one-half years. All of the DSA examinations were of diagnostic quality. We were surprised to find that 15% of angioplasty sites had undergone restenosis and, in addition, 12% of patients had new lesions. Because most of those patients were asymptomatic, such lesions would not have been detected by clinical assessment alone. Our angioplasty results compare favorably with other reported series. It is expected that DSA will play an increasingly important role in re-evaluation following treatment by angioplasty or surgery.
Angiography↗
Digital subtraction arteriography in the diagnosis of renovascular hypertension.
Renal digital subtraction arteriography (RDSA) is a relatively safe, simple, and inexpensive means of detecting the presence of renovascular disease in hypertensive patients. We report our own 15-month experience with RDSA, performed on 166 patients because of hypertension, and review the literature. Twenty-eight of the patients had arteriography. Using this as a measure, the sensitivity of RDSA was 83% and its specificity 96%. RDSA findings are usually conclusive. Addition of plain films following the procedure permits evaluation of renal parenchyma, collecting systems, ureters, and bladder. Arteriography should be reserved for those patients with positive RDSA to be treated by surgery or angioplasty, and for the small number of patients who have a non-diagnostic RDSA. If renal vein renin sampling is done first, RDSA may be performed at the same time. As RDSA becomes more available there will be little place for rapid sequence urography in the investigation of hypertension. In patients suspected of having renovascular hypertension, the primary mode of investigation should be renal DSA.
Catheterization↗
Radiographic analysis of the course of Legionella pneumonia.
The radiographic findings in the acute phase of Legionella pneumonia are generally non-specific and have been previously documented. A retrospective assessment of 12 patients with this bacterial pneumonia revealed that resolution of the radiographic findings was prolonged in five. The predominant feature in such patients is the transient finding of interstitial consolidation following the air-space consolidation, not unlike that of Mycoplasma or viral pneumonia. Eventual return to normal was evident in three patients and residual parenchymal fibrosis was noted in two patients.
Adult↗