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Biomedical subjects

D Swanson

Publications and source records attributed to D Swanson.

52 records · Page 3Linked to original sources
PubMed1984

Imaging of inflammatory processes with labeled cells.

Radionuclide techniques for localizing inflammatory processes had relied heavily upon 67Ga-citrate until McAfee and Thakur described the technique for the radiolabeling of leukocytes with 111In-oxine. Since their initial description in 1976 there has been continued development of the radiopharmaceutical, as well as clinical efficacy. At present 111In-labeled leukocytes continue to be handled as an investigational new drug but this has not greatly limited its clinical availability. Indium-111 leukocytes are the agent of choice for evaluation of patients with fever of unknown origin, osteomyelitis, and prosthetic graft infections; and preliminary data shows great promise in the area of detecting reoccurrence of inflammatory bowel disease. This article attempts to review currently accepted uses of 111In leukocytes as well as potential areas of application.

Abscess↗
PubMed1983

Elementary osmotic pump for indomethacin.

Based on the principles of an elementary osmotic pump, systems were designed to deliver indomethacin in solution at a constant rate, Z, to contain a total amount of drug, Mt, and to deliver 80% of their content at time t80. To allow selection of the optimal delivery rate into the body, three different prototypes were prepared with respective values for Z, Mt, and t80 of: 7 mg/hr, 85 mg, 11 hr; 9 mg/hr, 85 mg, 8 hr; and 12 mg/hr, 85 mg, 6 hr. These systems were found to deliver 70% of each system's contents at zero-order rates. Delivery rates were independent of pH, method of measurement, and stirring rate. In keeping with these results, the systems in the GI tract of dogs delivered at the same rate as in vitro, which qualifies the in vitro test as a bioanalogous method predictive of the in vivo performance of the dosage forms. Preliminary results in normal volunteers yielded similar urinary recoveries, while plasma profiles were different from each other and distinct from those following conventional capsules.

Animals↗
PubMed1983

A conveniently prepared Tc-99m resin for semisolid gastric emptying studies.

A polystyrene resin, suitable for semi-solid gastric emptying studies, was rapidly (less than 20 min) and conveniently prepared using commercially available reagents. Using the outlined procedure, Chelex-100 resin bound Tc-99m with greater than 98% labeling efficiency. The resulting Tc-99m Chelex-100 resin demonstrated excellent in vitro and in vivo stability. The clinical application of Tc-99m Chelex-100 resin, mixed with oatmeal, was tested in normal subjects and in various patient groups, including diabetic autonomic neuropathy, pyloric obstruction, postoperative dumping syndrome, and morbidly obese patients before and after gastroplasty.

Administration, Oral↗
PubMed1983

Onchocerciasis in Ecuador. I. Prevalence and distribution in the province of Esmeraldas.

In the province of Esmeraldas in Ecuador, 11 endemic foci of onchocerciasis were identified. The major focus, located on Rio Cayapas, consisted of 65 contiguous positive communities with an average infection rate of 51.1%. A distance-dependent characteristic of the onchocerciasis infection suggested that the transmission was centered principally in the areas near the head-waters of the river. This area, inhabited primarily by the indigenous tribe, Chachi, with an infection rate of 85%, was considered an area of hyperendemicity. Towards the river's mouth, where the majority of the inhabitants were Blacks, the rate of infection was 7%. The endemic focus located on Rio Santiago, populated entirely by Blacks and consisting of 17 contiguous positive communities, had an average infection rate of 18.8%. Again, the highest rate of infection, 33%, occurred in the upper reaches of the river. Resulting from the transient and migratory activity of some microfilariae-positive persons, 9 other isolated foci were found dispersed throughout the province. The infection rate of each focus was distinct, reflecting geographical location and ethnic composition. All foci other than the interior regions of Rio Cayapas were areas of hypoendemicity.

Adolescent↗
PubMed1983

Onchocerciasis in Ecuador. II. Epidemiology of the endemic foci in the province of Esmeraldas.

The epidemiology of infection was studied in all endemic foci of onchocerciasis in the province of Esmeraldas in Ecuador. The incidence of infection and the density of microfilariae in the skin, both greater in males than females, increased with age, reaching highest levels at 40-45 years in males and at 60 years and older in females. In the hyperendemic area males and females had the same rate of infection, but the microfilarial density in males exceeded that in females. In the hypoendemic areas males had a higher infection rate than females, but females registered a higher density of microfilariae in the skin. The incidence and location of the onchocercal nodules correlated closely with the density of microfilariae. Adults, aged 50-54 had the highest prevalence of onchocercal nodules, which occurred primarily in the thorax and pelvic regions. Children aged 0-14 years showed a low prevalence of nodules, the head region being the primary site. Of the two diagnostic methods used to detect the presence of microfilariae, most of the diagnoses (85.6%) were made by skin biopsies as compared to those made by the Mazzotti test (14.4%).

Adolescent↗
PubMed1981

Embolization of renal carcinoma.

Preoperative transcatheter embolization of a renal neoplasm is helpful to the urologist, especially with large, hypervascular tumors. When combined with nephrectomy and hormonal therapy, it offers promise in the management of patients with renal carcinoma. Delay between embolization and nephrectomy seems to be important, but the optimal time for stimulating a therapeutic response has not been established. Among 49 patients in this series with known metastases, occlusion of the renal artery followed 4 to 7 days later by nephrectomy and hormonal therapy changed the course of the disease, producing a 36% response rate.

Adult↗
PubMed1979

Arterial occlusion in the management of pain from metastatic renal carcinoma.

Arterial embolization was performed in nine patients with metastases from renal carcinoma who had severe pain resistant to conventional therapy. Patients with metastases in the ilium (four), the lumbosacral spine (one), and the base of the skull (one) experienced pain relief lasting from one to six months. The other three patients, who had metastases in the proximal femur, underwent preoperative embolization to facilitate tumor curettage and internal hip fixation. No significant complications were seen with this therapeutic approach.

Aged↗
PubMed1978

Clinical comparison of cardiac blood pool visualization with technetium-99m red blood cells labeled in vivo and with technetium-99m human serum albumin.

Technetium-99m red blood cells (Tc-RBC) labeled by an in vivo technique were compared with two preparations of Tc-99m human serum albumin (HSA) for cardiac blood-pool imaging. Relative distribution of the tracers was analyzed on end-diastolic frames of gated blood-pool studies and on whole-body (head to mid-thigh) anterior pinhole images. The Tc-RBC demonstrated greater relative percentage localization in the cardiac blood pool, higher target-to-background ratios in the left ventricle, and less liver concentration. For cardiac blood-pool imaging, Tc-RBC labeled by the in vivo approach appears to be superior to the two Tc-HSA preparations studied.

Cardiac Volume↗
PubMed1976

Retinol- and retinoic acid-binding proteins: occurrence in human retina and absence from human cultured fibroblasts.

Low-molecular-weight retinol- and retinoic acid-binding proteins were shown to be present in the soluble fraction of human retinal tissue but absent from human fibroblasts grown in tissue culture. By the use of gel filtration and comparison with bovine retinal tissue, the human intracellular binding proteins were found to have molecular weights of approximately 17,000 daltons, which are comparable to the molecular weights of bovine intracellular binding proteins. The quantity of retinoic acid bound exceeded that of retinol by about eightfold.

Animals↗
PubMed1975

A new, rapid fluorometric determination of retinol in serum.

A new procedure for the determination of retinol (vitamin A alcohol) in blood has been devised. It consists of direct measurement of the fluorescence of retinol (excitation 335 nm.; emission 458 nm.) in diluted serum, and is considerably more rapid than any previous method. Such measurements are feasible because the intensity of fluorescence of retinol bound to its transport protein (retinol-binding protein) is sufficiently high that other natural occurring fluorescent substances in blood do not interfere significantly. When the new method was compared to a conventional procedure employing extraction and chromatographic separation of retinol on columns of alumina, the correlation coefficient was 0.85.

Adult↗
PubMedDate not supplied

Radical cystectomy for invasive bladder cancer in the octogenarian.

The incidence of bladder cancer increases with age. As the population lives longer, an increasing number of patients 80 years of age or older will develop invasive bladder cancer. In this study, we reviewed the outcome of 33 patients age 80 years or older treated with radical cystectomy and ileal conduit urinary diversion. Five patients received neoadjuvant chemotherapy, and 2 had salvage cystectomy after failure of external beam radiation therapy. The median age was 82 years, and the median hospital stay was 12 days. There were no perioperative deaths. Twenty-seven complications occurred in 20 patients (60.6%), of which 17 were minor (63%) and 10 were major (37%). There was no difference in the rate of complications in patients receiving neoadjuvant treatment compared to the group treated with cystectomy alone. The median survival was 3.5 years. Our results demonstrate that radical cystectomy and ileal conduit urinary diversion should not be withheld from patients on the basis of age.

Age Factors↗
PubMedDate not supplied

Interpreting office radiographs: a research-based curricular prototype for training family practice residents.

Radiographic film interpretation is one area of the family practice residency training curriculum that has been given little focused emphasis. Starting with a series of studies into the office practice of radiology by family physicians to define need, content, and interpretation skill level, and following a systematic curriculum design process, the authors developed a comprehensive curriculum for teaching office X-ray interpretation to family practice residents. The final curricular prototype consists of: 1) a complete set of curriculum objectives; 2) a written monograph; 3) a set of instructional X-rays; and 4) a set of evaluation films. This research-based curriculum development process may serve as a model for developing other educational components for family practice residency training.

Curriculum↗