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Biomedical subjects

A H Robbins

Publications and source records attributed to A H Robbins.

At least 55 records · Page 3Linked to original sources
PubMed1983

Portal architecture: a differential guide to fatty infiltration of the liver on computed tomography.

Fatty infiltration of the liver, like fatty lesions elsewhere in the body, typically appears as low-density areas on computed tomography (CT). Fatty infiltration of the liver should be considered in the differential diagnosis of homogeneous low-density hepatic lesions regardless of distribution or size. As a physiologic rather than anatomic change, fatty infiltration of the liver characteristically leaves the portal venous architecture unaltered. Although fatty infiltration of the liver typically presents with complete or near complete involvement, other unusual patterns may be encountered. In these atypical cases, recognition of the normal portal structures on CT aids in correct diagnosis.

Fatty Liver↗
PubMed1983

Iopamidol in lumbar myelography.

Iopamidol is a new, nonionic, water-soluble contrast material currently undergoing clinical trials for intravascular and intrathecal use in Europe and the United States. In this study, 12 patients underwent lumbar myelography with this agent. For each subject, up to 12 mL of iopamidol (at 200 mg I/mL) was employed. The myelograms obtained were highly satisfactory. No serious adverse reactions were observed. The most common side effect--headache--occurred in seven patients. However, six of the seven headaches were mild and transient, and did not require treatment. Nausea occurred in two patients, back pain in two patients, hypotension and hypertension each in one patient. All of these reactions were mild and self-limited. Iopamidol appears to be a safe and conveniently used agent for lumbar myelography.

Adult↗
PubMed1983

Age changes in body composition revealed by computed tomography.

Computed tomography scans were taken of 21 middle-aged men (M age 46.3 years) and 20 older men (M age 69.4 years) to measure differences in body composition with age. Overall, the older men weighed 8.2 kg less than the middle-aged men, and this difference was primarily the result of their having less lean tissue. Although fat mass was only slightly less in older men, there were clear distributional differences in fat between the age groups. Total abdomen fat area was similar in both groups, although the subcutaneous portion of the abdomen fat was less in the older men, and they had correspondingly greater intra-abdominal fat. Muscle areas of the leg and arm were significantly less in the older men, as were all lean tissues of the abdomen and chest. Analysis of fat accumulation between muscles of the abdomen and leg indicated fat infiltration into lean tissue in the older men. Causes of this apparent fat redistribution and lean body mass decline with age are presently unknown.

Adipose Tissue↗
PubMed1983

Iopamidol and meglumine diatrizoate: comparison of effects on patient discomfort during aortofemoral arteriography.

Iopamidol was compared with Renografin-60 (meglumine diatrizoate, Squibb) in a controlled, randomized double-blind study of 40 patients undergoing peripheral arteriography for arteriosclerotic occlusive disease to determine which agent caused less discomfort. Each patient was evaluated for objective signs of discomfort and subjective feelings of pain and heat. Monitoring was achieved by multiple physical examinations, chemical tests, electrocardiograms, and intra-arterial pressure recordings. It is concluded that iopamidol is safe and causes significantly less patient discomfort than Renografin-60.

Angiography↗
PubMed1982

Assessment of abdominal fat content by computed tomography.

Computed tomography (CT) produces thin cross-sectional radiographs that may prove very useful in body composition research. CT images of the abdomen allow computerized measurement of total fat area, and also enable the differentiation of subcutaneous fat from intraabdominal fat. The preset investigation examines whether a single CT scan of the abdomen provides an accurate indication of overall abdominal adiposity. Graphs of measurements from seven sequential scans of the abdomen in eight patients showed that rankings of total abdominal area, total fat area, subcutaneous and intraabdominal fat area are relatively consistent no matter which abdominal level is chosen. Correlations of 0.89 to 0.99 between single scans and the average values for all scans show that a single CT image contains the same information on adiposity as a series of scans. These results suggest that future CT studies of body composition can limit radiation exposure by using single scans at different anatomical sites. If only a single scan at one site can be obtained, the level of the umbilicus may be the most useful, because it contains the largest percentage of fat in the body, and best allows differentiation of intraabdominal from subcutaneous fat.

Abdomen↗
PubMed1982

Bleeding esophageal varices: treatment with vasopressin, transhepatic embolization and selective splenorenal shunting.

The fate of 359 consecutive alcoholic cirrhotic male patients with bleeding esophageal varices was determined through chart review and personal interview. Three historical periods (1966-70; 1971-75; 1976-80) were defined based on availability of different therapeutic modalities. Management of acutely bleeding varices by conservative, nonsurgical means, including embolization, was preferable to emergency surgery when considering 30-day mortality rates. Percutaneous transhepatic embolization of esophagogastric varices significantly improved the rate of control of hemorrhage and 30-day survival over previously employed nonsurgical methods. The combination of nonsurgical management of acute variceal hemorrhage followed by selective distal splenorenal shunting resulted in maximum salvage of the alcoholic cirrhotic patient.

Embolization, Therapeutic↗
PubMed1982

Iopamidol: a non-ionic contrast agent for peripheral arteriography.

Ten patients undergoing peripheral arteriography with iopamidol were evaluated in a carefully controlled Phase I study using a variety of objective and subjective tests of discomfort. There was minimal objective evidence of pain, and the patients reported that they perceived minor discomfort and a warm sensation during the contrast injections. Five patients who had previously undergone arteriography using 2 mg of lidocaine per ml of methylglucamine diatrizoate noted a marked decrease in discomfort when iopamidol was used. Opacification of peripheral arteries was excellent. Multiple physical examinations, chemical tests, electrocardiograms, and intra-arterial pressure recordings showed that iopamidol is safe.

Adult↗
PubMed1982

CT appearance of afferent loop obstruction.

Obstruction of the afferent loop may develop in patients who have had a Billroth type II gastrojejunostomy. This obstructed loop has a characteristic but initially confusing computed tomographic appearance that might be mistaken for multiple peripancreatic cystic masses. Three cases of afferent loop obstruction due to gastric carcinoma are reported. In each case, the length of the jejunal segment incorporated into the afferent loop determined the number of cystic masses evident at each scan level. Recognition of the typical anatomic configuration and uniform size of these cystic masses is key to the correct diagnosis.

Afferent Loop Syndrome↗
PubMed1981

Percutaneous catheter drainage of abdominal abscesses: a five-year experience.

We used computed tomography (CT) and ultrasonography for detection and localization of intra-abdominal abscesses. On the basis of these images, safe routes for diagnostic aspiration and percutaneous drainage were planned. Over these routes indwelling catheters were inserted to provide immediate decompression, evacuation, and continuous drainage until the abscess resolved. All patients received concomitant intravenous antibiotics. The treatment was used for 71 abscesses in 67 patients. Sixty-one abscesses (86 per cent) were satisfactorily drained. There were 11 complications (15 per cent). Six deaths were attributable to sepsis, three of which (4 per cent) were related to inadequate drainage. There was one recurrence (1 per cent) during a follow-up period ranging from one month to five years (means, 22.3 months). The mean duration of treatment was 20.2 days (range, five to 120 days). We conclude that percutaneous drainage is an effective method for treatment of abdominal abscesses and is indicated when sectional imaging demonstrates an accessible unilocular lesion.

Abdomen↗
PubMed1981

Computed tomographic angiography.

Computed tomographic angiography performed by the intravenous administration of contrast medium was evaluated in 86 vascular patients. This experience demonstrates a new approach to the evaluation of patients with symptomatic aortic aneurysms, in whom computed tomographic angiography will aid in evaluating the need for emergency surgery. Nonoperative patients are serially evaluated by computed tomographic angiography to detect significant changes in the geometric configuration of their aneurysms. Computed tomographic angiography was beneficial in the evaluation of the patency of vascular reconstructive procedures such as femoropopliteal bypass, aortoiliac bypass and application of a vena caval device. More clinical experience and possibly a rapid sequence technique are needed to evaluate patients with portasystemic shunts.

Abdomen↗
PubMed1981

Treatment of abdominal abscesses: comparative evaluation of operative drainage versus percutaneous catheter drainage guided by computed tomography or ultrasound.

Computed tomography and, to a lesser extent, ultrasonography provide detailed anatomic localization of intra-abdominal abscesses that permit precise percutaneous placement of catheters large enough to effect drainage. Using routes similar to surgical approaches, the authors have used this technique as definitive therapy for intra-abdominal abscesses. To assess its efficacy, the results in the 27 patients treated percutaneously over the last five years have been compared with the results in the 43 patients treated by operative intervention over the past ten years. In the percutaneous group, complications (4%), inadequate drainage (11%), and duration of drainage (17 days) were less than in the operative group (16%, 21% and 29 days respectively). These results indicate that percutaneous drainage is at least as efficacious as operative drainage and avoids the risks of a major operative procedure.

Abdomen↗
PubMed1981

An assessment of the role of scan speed in perceived image quality of body computed tomography.

Forty-three chest (noncardiac) and 75 abdominal computed tomographic (CT) examinations were studied by obtaining four sections of a pertinent area using 2.25-, 4.5-, 9-, and 18-second scan speeds. Chest scans obtained with the three faster speeds were perceived to be qualitatively similar to one another but were rated better than the 18-second sections. While these qualitative differences were statistically significant, most were relatively unimportant clinically. Analysis of the abdominal sections showed significant qualitative improvement with each successively faster scan speed. The only sections rated unreadable and/or showing large numbers of motion artifacts were abdominal studies, primarily 18-second studies. A statistically significant loss of diagnostic information was noted with 18-second scans, especially in the upper abdomen.

Evaluation Studies as Topic↗
PubMed1981

Computed tomographic scanning of the mediastinum in the staging of bronchogenic carcinoma.

We investigated the efficacy of 2-s breath-holding computed tomographic (CT) scans and standard posteroanterior and lateral chest roentgenograms in staging the mediastinum and pulmonary hill in lung cancer. Fifty-one comparisons were made in 49 patients thought to have non-small-cell carcinoma, consecutively chosen to be free of disseminated tumor, and to be suitable candidates for thoracotomy. The CT scans accurately predicted mediastinal neoplastic lymphadenopathy in 15 or 17 instances of proved mediastinal lymph node metastasis for a sensitivity of 88%; specificity was also high (94%) with a true-negative scan in 32 of 34 instances. Standard chest roentgenograms were much less sensitive (47%) than rapid CT scanning in mediastinal staging; there were false-negative interpretations in 9 of 17 instances. Specificity of the methods was the same. both CT scans and standard chest roentgenograms had a sensitivity of only 67% in detecting neoplastic hilar adenopathy; enlarged hilar nodes were noted in only 10 of 15 patients with proved hilar node metastasis. We concluded from this preliminary study that rapid CT scanning shows promise of being useful in the noninvasive staging of the mediastinum of patients with otherwise operable non-small-cell bronchogenic carcinoma; the technique also provides useful guidance during mediastinoscopy and may detect lymphadenopathy not so visualized, but CT scanning appears to have little advantage over standard posteroanterior and lateral chest roentgenograms in staging the pulmonary hill.

Adult↗
PubMed1980

Iron-sulfur clusters in Azotobacter ferredoxin at 2.5 A resolution.

X-ray crystallographic study of the ferredoxin-like protein (iron-sulfur protein III) from Azotobacter vinelandii has been extended to 2.5-A resolution. A 4.0-A resolution electron density map revealed that the molecule contains two Fe-S clusters of differing size and shape separated by 12 A (Stout, C.D. (1979) Nature 279, 83-84). Recent Mössbauer results by Emptage et al. (Emptage, M.H., Kent, T.A., Huynh, B.H., Rawlings, J., Orme-Johnson, W.H., and Münck, E. (1980) J. Biol. Chem. 255, 1793-1796) have shown that the molecule contains 7 iron atoms as a high potential iron protein-like Fe4 center and a novel 3-Fe center. The 2.5-A electron density map shows two distinctly different Fe-S clusters. The larger cluster consists of a tetranuclear [4Fe-4S] core ligated to the protein at each iron atom. The smaller cluster is distinctly planar and cannot be modeled with [2Fe-2S] or [4Fe-4S] structures. The best model for this cluster is a [3Fe-3S] core. The protein makes six contacts with this cluster.

Azotobacter↗