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Biomedical subjects

A Moss

Publications and source records attributed to A Moss.

At least 91 records · Page 5Linked to original sources
PubMed1986

Risk of seroconversion for acquired immunodeficiency syndrome (AIDS) in San Francisco health workers.

The occupational risk of acquiring acquired immunodeficiency syndrome (AIDS) virus infection in health workers exposed to AIDS patients and specimens was assessed by a serologic study at San Francisco General Hospital and collaborating research laboratories. A total of 101 medical workers without risk factors for AIDS were examined for antibodies to two isolates of the AIDS retrovirus (AIDS-associated retrovirus 2[ARV-2] and human T cell lymphotropic virus III). Most had heavy, long-term exposure to AIDS patients and 29 had been exposed by needlestick or mucocutaneous accident. None of the 101 had antibodies to ARV-2 by immunofluorescence or to HTLV-III by enzyme-linked immunosorbent assay and Western Blot.

Acquired Immunodeficiency Syndrome↗
PubMed1986

CT body stereotaxis: an aid for CT-guided biopsies.

A new body stereotaxic system used to facilitate CT-guided biopsies is described. By scanning through a triangle placed on the patient's skin, the method defines an entry point for the biopsy. An articulating arm is then used to aim the needle at the entry point and hold the needle at the correct angle. The arm can be angled so that complex approaches from one scan plane to another can be made in order to take biopsies of lesions beneath the diaphragm. Using the system, 23 of 25 lesions were hit on the first needle manipulation; two manipulations were needed for each of the other two lesions. In comparison with previous experience, procedure time was decreased and the numbers of needle manipulations and localization scans were decreased 75% and 90%, respectively.

Biopsy, Needle↗
PubMed1986

Ultrasound and the intestinal wall: experimental methods.

High-frequency, high-resolution ultrasound provides a new approach to imaging structures in the wall of the gastrointestinal tract. Questions about internal ultrasound include: is the ultrasound image specific for disease states, in which diseases will this technology add new and useful information not available from existing diagnostic studies, and what are the necessary characteristics for a system to accomplish these diagnoses? Answering these questions requires that precise correlations be made between the ultrasound image and pathology. We have developed a method to image a resected gastrointestinal tissue with ultrasound and to remove and examine the corresponding piece of tissue histologically. Changes in wall thickness, obliteration of layers, and changes in the characteristics of the tissue can be studied. We have shown that ultrasound can resolve the layers of the gut wall. This system should enable us to answer questions about which intestinal wall diseases are suitable for internal ultrasound imaging and characterize the engineering features of an optimal ultrasound system for clinical application.

Digestive System↗
PubMed1984

Early evaluation of coronary artery bypass grafts: CT or selective angiography.

A prospective study was performed in 27 patients to compare the value of computed tomography and selective angiography in assessing coronary artery graft patency in the early post-operative period. The sensitivity of CT to graft patency was 85% with no falsely patent determinations. Dynamic CT was not found useful in predicting graft stenosis. There were no complications associated with CT studies, and two related to selective angiography. It is concluded that CT is the procedure of choice for graft evaluation in the early post-operative period; but that angiography is mandatory for the assessment of late symptom recurrence. A review is made of the results described in previous series.

Blood Vessel Prosthesis↗
PubMed1983

Resection of gastrinomas.

Exploratory laparotomy and a search for gastrinomas was performed in 52 patients with the Zollinger-Ellison syndrome (ZES). Gastrinoma tissue was resected in 11 patients (21%), 6 (12%) of whom appear to have been cured. After surgery, serum gastrin levels in these six patients have remained normal from 10 months to 10 years. In the 46 other patients, tumor was unresectable because of metastases or multiple primary tumors (21 patients; 40%) or inability to find the tumor at laparotomy (21 patients; 40%). Multiple pancreatic islet cell adenomata were found in six of seven patients with multiple endocrine neoplasia (MEN), indicating that patients with this condition usually have diffuse involvement of the pancreas. The results of CT scans correlated with findings at laparotomy in 13 of 16 patients. The smallest tumor detected by CT scans was 1 cm in diameter. CT technology is more accurate in finding gastrinomas now than in the past and has a useful role in preoperative evaluation. The possibility of resection should be seriously considered in every patient with Zollinger-Ellison syndrome. Abdominal CT scans, transhepatic portal venous sampling, and laparotomy should be used to find the tumor and to determine whether it is resectable. Using presently available methods, it should be possible to cure about 25% of patients with gastrinomas who do not have MEN and over 70% of those without MEN who appear to have a solitary tumor. Total pancreatectomy may be necessary to cure some patients with MEN, but that operation is rarely justified. The morbidity and mortality of surgical attempts at curing this disease have become minimal; we have had no deaths or serious complications following such operations in over 10 yrs. Total gastrectomy and indefinite use of H2-receptor blocking agents are the therapeutic options for patients with unresectable gastrinomas. Because H2-receptor blocking agents fail to control acid secretion in many patients after several yrs of therapy, total gastrectomy is indicated in a large proportion of patients whose tumors cannot be resected. Total gastrectomy in patients with ZES is also safe using current techniques; our last death following this operation for ZES occurred 15 yrs ago.

Adenoma, Islet Cell↗
PubMed1983

CT of the thoracic duct.

The ability of computed tomography to demonstrate the normal anatomy of the thoracic duct was investigated after lymphangiography in 20 patients without evidence of chest diseases on the plain films. The entire opacified thoracic duct can be easily imaged from its origin at the thoraco-abdominal level, up to its arch, which enters the venous blood stream, usually at the left subclavian-jugular confluent. Variations of the arch of the duct have been observed in our series. The ability to detect the non-opacified duct with CT was also assessed in 80 patients. Imaging of part or totality of the lower, mid and upper segments of the thoracic duct is possible respectively in 81, 54 and 69 per cent of subjects. The arch of the duct was displayed in 57 per cent. Knowledge of the normal anatomy of the thoracic duct is important since it can be involved in many diseases of the posterior mediastinum and of the thoracic outlet.

Adult↗
PubMed1982

Localization of parathyroid adenoma by computed tomography.

Sixteen consecutive patients with the clinical diagnosis of hyperparathyroidism, nine with and seven without previous surgery, had computed tomography (CT) examinations preoperatively to evaluate the use of CT in localizing parathyroid adenomas. The patients were scanned at 5 mm intervals from the level of the hyoid bone to the lung apex. Scanning of the mediastinum was performed at 10 mm intervals from apex to lung base. Computed tomography correctly identified prospectively the site of the adenoma in 10 of 13 patients (77%), with surgically proven adenomas. In retrospect, all 13 adenomas could be identified. One false positive diagnosis of adenoma was made. Our study suggests that CT may be beneficial in the preoperative localization of parathyroid tumors, particularly in ectopic locations.

Adenoma↗
PubMed1981

Clinical study of pheochromocytoma.

Seventeen patients underwent 22 operations for pheochromocytoma over a 26 year period. The patients included 11 in three kindreds of familial pheochromocytoma and 6 with sporadic tumors. The diagnosis was usually suggested by the patient's history. Confirmation of the diagnosis frequently required repeated testing for urinary or plasma catecholamines. Arteriography was the most effective method of preoperative tumor localization. Two tumors were proven nonfunctional. Others secreted either norepinephrine or epinephrine and norepinephrine. The familial patients showed a high incidence of multiple, bilateral and extraadrenal lesions. In contrast to previous reports, the familial tumors were found more often in the right than in the left adrenal gland. HL-A genotyping analysis of the sporadic and familial patients failed to demonstrate any HL-A antigen association or interdependent segregation of tumor and HL-A antigens within kindreds.

Adolescent↗
PubMed1980

Objective performance measurements versus perceived image quality in intensified fluoroscopic or photospot images.

The relationship between perceived image quality and measurable performance parameters of an intensified fluoroscopic image, viewed via a TV monitor or recorded on 105mm film, was investigated. Four specially manufactured image tubes, differing significantly in x-ray absorption efficiency, spatial resolution, and/or contrast resolution, were studied. Quantitative measurements of tube performance included the conversion factor, the quantum detection efficiency, the limiting resolution, the contrast ratio, and the contrast-detail characteristics. An assessment of the quality of clinical images was made by two radiologist-observers, working independently and without knowledge of any quantitative results. The observers were asked to rate the noise, lag, resolution, and contrast of the images during a variety of fluoroscopic procedures on each tube. While general agreement was found between the quantitative measurements and the radiologists' perceptions of image quality, the noise and contrast performance of an intensifier had greater influence on the radiologists' judgment of image quality than did resolution.

Fluoroscopy↗
PubMed1980

Computerized tomography in the quantitative assessment of tumour response.

While Computerized Tomographic (CT) scans have been a valuable asset to radiotherapy treatment planning, their role in the critical assessment of tumour response has been less well defined. Recent refinements in radiotherapy treatment techniques have intensified the need for non-invasive methods to evaluate the local control of inaccessible neoplasms. In this study, 20 cases in which both pre- and post-treatment CT scans were available up to 27 months post-therapy were reviewed. The majority of the patients had pancreatic carcinoma. In both pre- and post-therapy scans, the tumour volume was calculated from contours outlined on sequential CT slices. These interpretations were compared with surgical findings, clinical course and patient survival. The rate of the primary tumour regression had little bearing on the clinical outcome. However, there was CT scan evidence of initial local tumour stabilization or regression in > 80% of the cases. In addition, CT scan evidence of tumour progression was correlated with clinical progression in > 90% of the patients. This suggests that a growth delay analysis might be possible with the use of CT scans, at least for the evaluation of pancreatic carcinoma.

Humans↗
PubMed1979

Abnormalities of central contrast sensitivity in glaucoma.

The detectability of foveally presented low-contrast flickering stimuli was determined for glaucoma patients, ocular hypertensives, and normal control subjects. Two types of stimuli, a homogeneous flickering field, and a counterphase flickering grating of low spatial frequency, were presented on a screen subtending 4 degrees of visual angle. The average of the contrast sensitivities to these two simuli (defined as the dynamic response coefficient) was consistently lower in glaucomatous than in normotensive eyes. The dynamic response coefficient was also below normal in half the ocular hypertensive eyes.

Adult↗
PubMed1979

Argyria: clinical implications of exposure to silver nitrate and silver oxide.

This article reports the clinical findings in a work force of 30 individuals who were exposed to silver nitrate and silver oxide. Six individuals had argyria and 20 had argyrosis (deposition of silver in the eye). Measurements of blood silver levels were included as part of the examination. The results of this examination generally support the benign nature of argyria, although the question of silver causing a decrement in kidney function and night vision is not settled. Periodic slit lamp examinations as well as monitoring of silver air concentrations are necessary to assure that engineering controls are actually limiting worker exposure to silver.

Adult↗
PubMed1978

Lack of association of histocompatibility antigens with primary open-angle glaucoma.

Eighty-seven patients (35 with primary open-angle glaucoma, 20 with angle-closure glaucoma, and 32 controls) underwent HLA typing of peripheral lymphocytes. Sixteen specificities were detected at the A locus, 19 at the B locus, and four at the C locus. No significant differences were found between patients with either type of glaucoma and control patients.

Ethnicity↗
PubMed1978

CT scanning and ultrasound in the evaluation of pancreatic pseudocysts: a preliminary comparison.

A retrospective review of 12 surgically proved cases of pancreatic pseudocyst was performed. CT correctly demonstrated 6/8 uncomplicated pseudocysts and 4/4 infected pseudocysts. Ultrasound identified 7/8 uncomplicated and 2/4 infected pseudocysts. Errors by one modality are due to limitations not shared by the other method. This suggests a basis for the complementary use of CT scanning and ultrasound in the evaluation of suspected pancreatic pseudocysts.

Adult↗
PubMed1978

The effect of supervised tooth cleansing every second week on dental caries in Danish school children.

The purpose of the present study was to determine the effect of a program of regular plaque control carried out by a group of school children, supervised and assisted by dental personnel. Approximately 200 children 5--13 years of age were randomly assigned to two groups. Children in the experimental group performed supervised toothbrushing every second week during the school year, using a disclosing solution. Following this, a disclosing solution was reapplied and the remaining plaque removed by dental personnel. Both groups participated in fortnightly fluoride rinses, regular toothbrushing instruction and various educational activities. Mean dental caries increment at the precavitation level during the 2-year experimental period was 19 per cent lower in the experimental group than in the control group. At the cavitation level the difference was 17 per cent. None of these differences were statistically significant. The conclusion of the present study was that only limited effect of regular removal of dental plaque as performed by school children could be demonstrated.

Adolescent↗