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Biomedical subjects

D P Swanson

Publications and source records attributed to D P Swanson.

At least 19 recordsLinked to original sources
PubMed1997

Evaluation of laminin peptide fragments labeled with indium-111 for the potential imaging of malignant tumors.

The laminin peptide fragments GYIGSR-NH2 and CDPGYIGSR-NH2 are known to bind to a 67-kDa laminin receptor. This receptors is understood to be expressed at higher than normal levels in malignant tumor cells, particularly those of breast and colon carcinomas. Peptides DTPA-GYIGSR-NH2 (1), DTPA-(GYIGSR-NH2)2 (2), DTPA-CDPGYIGSR-NH2 (3), DTPA-(CDPGYIGSR-NH2)2 (4), and negative control DTPA-GAGAGA-NH2 (5) were prepared by solid-phase peptide synthesis. All five DTPA-conjugated peptides were subsequently radiolabeled with 111In and their tissue distribution evaluated in mice bearing C3H tumors. 111In-3 and 111In-4 showed the highest specific tumor localization. These preliminary data support further study of radiolabeled petide fragments for the potential detection of malignant tumors of the breast and other organs.

Amino Acid Sequence↗
PubMed1996

Radiopharmaceuticals as orphan drugs.

Rare diseases and conditions are defined as diseases or conditions that affect less than 200,000 individuals in the United States. Because of the limited population suffering from any given rare disorder, there is little economic motivation for the development of drug products for its diagnosis or treatment. Also, frequently these rare diseases are misdiagnosed or undiagnosed due to a lack of familiarity with their symptoms and course. Thus, these rare disorders are commonly referred to as orphan diseases or conditions. To address this problem, legislation has been enacted that provides for incentives for the development of drug products for rare diseases or conditions (i.e., orphan drug products). Nuclear medicine scientists can take advantage of these incentives in the development of orphan radiopharmaceuticals for the treatment or diagnosis of rare diseases or conditions. Nuclear medicine physicians should know where information on orphan diseases and orphan radiopharmaceuticals can be obtained to maximize the care of their patients.

Disease↗
PubMed1995

Dosage of gadoteridol and adverse reactions relative to gadopentetate.

Compliance with an institution's dosage guidelines for gadoteridol was determined, and adverse reactions to gadoteridol and gadopentetate were compared. Departmental policy in March 1993 set the standard dose of gadoteridol at 0.1 mmol/kg. A dose of 0.05 mmol/kg was set for patients with suspected acoustic neurinomas or pituitary microadenomas. Guidelines allowing a high dose of 0.2 or 0.3 mmol/kg were also established for specific indications involving suspected metastatic disease or inadequate contrast enhancement at the standard dose. Data on gadoteridol use were collected concurrently from May 1993 to January 1994 and included the dose, the indication for the dose, and any adverse reactions. Safety data for patients who had received gadopentetate between June 1988 and March 1990 were also collected and reviewed. The subjects in this retrospective analysis represented the same broad population as those involved in the concurrent evaluation of gadoteridol use. The frequency and types of adverse events in the two groups were compared. During the gadoteridol-review period, 8377 patients underwent magnetic resonance imaging studies; 3558 (42.5%) of them received gadoteridol. Of the 3558 doses given, 3375 (94.9%) were 0.1 mmol/kg (the standard dose). Compliance with the guidelines for nonstandard doses was 90% for the 0.3-mmol/kg dose, 74% for the 0.2-mmol/kg dose, and 39% for the 0.05-mmol/kg dose. There were 101 adverse reactions to gadoteridol in 75 (2.1%) of the 3558 recipients. The reactions were mild to moderate and self-limiting. Records for 4892 gadopentetate recipients were analyzed. There were adverse reactions in 62 patients (1.3%). Again, most reactions were mild to moderate. The use of gadoteridol at a medical center generally complied with institutional guidelines. Gadoteridol was well tolerated whether given in standard or high doses. The frequencies and types of adverse reactions to gadoteridol and gadopentetate were similar.

Contrast Media↗
PubMed1994

Pharmacist-managed monitoring of adverse reactions to contrast media.

A pharmacist-managed program for reporting, treating, and monitoring adverse drug reactions (ADRs) to contrast media is described. The radiology pharmacist at a 1000-bed multihospital medical center worked with the radiology department to revise departmental policies and procedures for reporting ADRs to contrast media. Under the revision, an ADR report must be completed and forwarded to the pharmacy department and radiology pharmacist for review. In the radiology department itself, ADRs must be documented in the computerized radiology information system in two fields, the patient's radiology file and the radiology study report. The radiology pharmacist developed guidelines for preventing and treating ADRs to contrast media. Boxes containing drugs specifically indicated for the treatment of these ADRs were distributed throughout the radiology department. The radiology pharmacist prepares a quality improvement report each quarter. ADRs documented in the patient's radiology file and in the radiology study report are compared with the total number of ADRs reported. The incidence of ADRs is determined and compared with that for previous quarters and with published data. The treatment of each reaction is evaluated for compliance with the guidelines, the need for follow-up, and any unusual problems. Between July 1991 and December 1992, ADR documentation in the radiology file and in the radiology study report increased substantially in several divisions of the radiology department. The rates of ADRs to contrast media remained fairly constant and paralleled published rates. Compliance with the treatment guidelines was excellent. Pharmacist involvement led to improved reporting of adverse reactions to contrast media in a radiology department and to greater awareness of measures for treating and preventing them.

Adverse Drug Reaction Reporting Systems↗
PubMed1991

Acute reactions to intravascular contrast media: types, risk factors, recognition, and specific treatment.

Acute, potentially life-threatening systemic reactions to contrast media are less frequent with lower osmolality, nonionic contrast agents, but they are not totally eliminated. Severe reactions remain a reality in all radiology departments. Typical reactions to contrast media include nausea and/or vomiting, scattered to extensive urticaria, bronchospastic reaction, hypotension (isolated) with compensating tachycardia, anaphylactoid reaction, vagal reaction, cardiovascular collapse, convulsion, and seizure. For each type of reaction, rapid recognition and initiation of specific corrective therapy enhance response and minimize side effects of drugs. Specific drugs for treating each reaction type are reviewed, including recommended dose, contraindications, and alternative choices. An approach to the high-risk patient and prevention of acute systemic reactions is discussed and pretreatment protocols are outlined.

Anaphylaxis↗
PubMed1988

African American adolescents: adaptational processes and socioeconomic diversity in behavioural outcomes.

The study was concerned with determining the relationship of economic diversity to stress reactivity. Parental ratings of competence and behavioural problems were obtained for very young adolescents following a long-term and highly acute stress: the Atlanta youth murders. Intellectual and identity-formation data obtained both before and after the crisis were analyzed with the parental ratings of youth competence and behavioural problems. Consistent socioeconomic status (SES) links between the manifestation of behavioural problems and the display of competencies were obtained; lower income (LI) youths manifested more problems and fewer competencies. The findings were more pronounced for LI males. Personal identity was a significant predictor of school competence. School self-esteem was a predictor of academic performance. The manifestation of behavioural problems was significantly predicted by cognitive performance variables. The findings are discussed in terms of variations in adaptational strategies mediated by socioeconomic status and psychological factors.

Achievement↗
PubMed1987

Failure of technetium-99m sulfur colloid uptake by the femoral head. Aseptic necrosis or normal variation?

The hips of 79 asymptomatic patients having Tc-99m sulfur colloid liver/spleen scans were imaged. Patients were not studied if they had a disease associated with nonvisualization of the femoral heads. The first group consisted of 47 consecutive patients who were imaged in a neutral position. Eighteen right and 18 (38.3%) left hips showed no activity. The second group consisted of 32 consecutive patients who were imaged in an internally rotated position. Seven (21.9%) right and nine (28.1%) left hips showed no activity. This study concludes that failure of uptake of Tc-99m sulfur colloid by the femoral head is seen in a sufficiently large group of patients to limit its use in diagnosing aseptic necrosis.

Femur Head↗
PubMed1987

Portal hypertension workup by DSA.

To provide information for preoperative planning, combined, selective intravenous (IV) and intraarterial (IA) digital subtraction angiography (DSA) studies were performed on 42 portal hypertension patients scheduled for portal systemic shunt procedures. Selective IV-DSA was performed to demonstrate the hepatic venous system, left renal vein, and inferior vena cava. Portal venous anatomy, direction of flow, and portal systemic collaterals were evaluated by selective IA-DSA. In addition, selective IA-DSA was performed postoperatively on 8 patients to assess shunt patency. Technically adequate DSA studies, suitable for surgical planning or postoperative assessment, were obtained in all of the 50 patients examined. Patient or internal organ motion was not a limiting factor in any study. Such use of DSA represents an efficacious, safe, and cost-effective alternative to conventional film-screen angiography for the evaluation of patients with portal hypertension.

Angiography↗
PubMed1986

Developing marketing pamphlets for diagnostic radiology services.

The marketing of professional services requires an approach that differs from that utilized in the conventional marketing of products and services. This article describes the considerations that were involved in the development and implementation of marketing pamphlets for diagnostic radiology services.

Hospital Bed Capacity, 500 and over↗
PubMed1986

Evaluation of intravascular low-osmolality contrast agents.

The chemistry of low-osmolality contrast agents is reviewed, the effects of these agents on vascular and organ physiology are compared with the effects of conventional ionic contrast media, and guidelines for intravascular use of the low-osmolality agents in selected high-risk patients are presented. Three low-osmolality contrast agents, the nonionic media iohexol (Omnipaque, Winthrop-Breon) and iopamidol (Isovue, Squibb) and the dimeric medium ioxaglate meglumine-sodium (Hexabrix, Mallinckrodt) have recently been introduced into the contrast-media market. Compared with conventional ionic contrast media, these new agents demonstrate approximately one third of the osmolality per given iodine concentration (degree of roentgenographic opacification). Therefore, the risks of hyperosmolarity-induced reactions to contrast media are lower with the new agents. The low-osmolality agents may be associated with a reduced incidence of contrast-media-induced hypersensitivity reactions. Because of their lower osmolality, these agents produce less vessel dilation, vascular endothelial damage, and associated pain and discomfort than equi-iodine concentrations of the conventional ionic media. They also demonstrate a reduction in the incidence and severity of contrast-media-induced renal vasoconstriction and proteinuria, hemodynamic alterations, negative chronotropic effects, depression of myocardial contractility, and neurotoxicity in the presence of an altered blood-brain barrier. These low-osmolality agents produce fewer undesirable physiological effects than conventional contrast agents, but the cost of the new products can be more than 10 times as great. Therefore, the new products should be used selectively in patients known to be at increased risk for reactions to intravascular contrast media. A scoring system was developed to permit rapid recognition of documented single or multiple risk factors and subsequent determination of whether to administer a low-osmolality agent.

Blood Circulation↗
PubMed1985

omega-123I-hexadecanoic acid metabolic probe of cardiomyopathy.

The utility of omega-123I-hexadecanoic acid myocardial scintigraphy as a metabolic probe of cardiomyopathies was investigated. Sixteen patients with a variety of cardiomyopathies and myopathies that involve cardiac muscle and ten volunteers were imaged in the postabsorptive state in a 40 degrees LAO projection after a standard dose of omega-123I-hexadecanoic acid. An elimination T1/2 was calculated from the left ventricular myocardial time-activity curve. An uptake index, corrected for chest wall attenuation, was also computed in 7 of 10 volunteers and 8 of 16 patients. Of the 16 patients, only 2 had distinctly abnormal omega-123I-hexadecanoic acid myocardial tracer kinetics. The first patient had a metabolic disorder of which carnitine deficiency was one component. The second patient had endocardial fibroelastosis, a process which has been linked to disorders which deprive the myocardium of oxygen and energy. Therefore, the cardiomyopathy may have been caused by some abnormality of cardiac metabolism other than carnitine deficiency. Although of limited utility in the overall cardiomyopathic population, omega-123I-hexadecanoic acid myocardial scintigraphy should be further investigated as a screening test for carnitine deficiency and related metabolic abnormalities in patients at risk.

Adolescent↗
PubMed1985

Morbid obesity treated by gastroplasty: radionuclide gastric emptying studies.

Mechanisms by which gastroplasty for morbid obesity causes weight loss are poorly understood. We studied the role of altered gastric emptying in 50 patients before surgery, 1-4 weeks after surgery, and 2-24 months after surgery using technetium-99m pentetate in water for liquid meals and a Tc-99m styrene divinylbenzene copolymer resin in oatmeal for semisolid meals. We determined the emptying half-times of the stomach before and after surgery in the proximal and distal compartments. The proximal compartment emptied promptly in the early and late postoperative periods. The distal compartment emptied liquids at rates similar to those before surgery, while the late postoperative emptying of semisolids was significantly faster. The stoma connecting the two compartments thus permits rapid transit of liquids and semisolids without delay of distal compartment emptying. No correlation was seen between the emptying half-times or changes thereof and eventual weight loss. Delayed gastric emptying is therefore not the mechanism for satiety and weight loss after gastroplasty has been performed.

Adult↗