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Biomedical subjects

F L Datz

Publications and source records attributed to F L Datz.

At least 37 records · Page 2Linked to original sources
PubMed1994

The efficacy of indium-111-polyclonal IgG for the detection of infection and inflammation.

UNLABELLED: The purpose of this study was to determine the efficacy of 111In-polyclonal immunoglobulin (IgG) for the diagnosis of infection or inflammation. METHODS: Fifty-three patients with suspected infection were prospectively studied. Each underwent an 111In-polyclonal IgG study; biopsy, surgery, additional nuclear medicine scans and radiographic studies were used to confirm the IgG scan results. RESULTS: The polyclonal IgG scan had a sensitivity of 97.9% and a specificity of 94% for infection or inflammation. When only infection or severe inflammation such as bowel infarction was considered, the sensitivity remained the same but the specificity fell to 83%. Chronic infections were detected equally as well as acute infections. Antibiotics, steroids, anti-inflammatory agents, diabetes and diminished renal function did not affect scan sensitivity. There were no adverse reactions to the radiopharmaceutical. Three patients underwent extended imaging. Their scans stayed positive for an average of 8 days. Three patients treated for infection had their scans turn negative on repeat study, confirming the efficacy of their antibiotic therapy. CONCLUSION: Indium-111-polyclonal IgG is an effective imaging agent of infection and/or inflammation that is useful in a variety of infections and in severe inflammatory diseases. The ease of preparation and safety make it an attractive alternative to labeled leukocytes.

Adult↗
PubMed1993

The use of computer-assisted diagnosis in cardiac perfusion nuclear medicine studies: a review (Part 2).

Computer-assisted diagnosis (CAID) is commonly used to evaluate cardiac nuclear medicine studies such as thallium perfusion scans. Part I of this series (Journal of Digital Imaging, Vol 5, No 4, pp 209-222) reviewed the basic theory underlying CAID in nuclear medicine and its use in planar thallium imaging. This review discusses the application of CAID to SPECT perfusion studies.

Artifacts↗
PubMed1993

The use of computer-assisted diagnosis in cardiac perfusion nuclear medicine studies: a review (Part 3)

Computer-assisted diagnosis (CAID) is commonly used to evaluate cardiac nuclear medicine studies such as thallium perfusion scans. Part 1 of this series (Journal of Digital Imaging, 5:209-222, 1992) reviewed the basic theory underlying CAID in nuclear medicine and its use in planar thallium imaging. Part 2 discussed the application of CAID to SPECT perfusion studies (Journal of Digital Imaging, 6:1-15, 1993). This article reviews new variations of CAID programs for SPECT imaging and the application of expert systems and neural networks to CAID of nuclear medicine perfusion studies.

Algorithms↗
PubMed1993

Comparison of methods for identifying early methotrexate-induced hepatotoxicity in patients with rheumatoid arthritis.

Hepatotoxicity may complicate therapy with methotrexate in patients with rheumatoid arthritis. Prevention of cirrhosis may depend upon early identification of liver damage, usually accomplished by serial biopsy. To determine the adequacy of noninvasive methods for identifying hepatotoxicity, 22 sets of data were obtained in patients undergoing therapy with methotrexate for rheumatoid arthritis. Comparisons were made between liver biopsy, hepatocellular enzymes and two noninvasive radioisotopic methods that have been shown to be abnormal in hepatocellular disease: the rate constant of excretion of the 14C-aminopyrine and the time from injection to peak hepatic activity of 99mTc-diisopropylimidodiacetic acid. The hepatocellular enzymes and the time-to-peak-activity of diisopropylimidodiacetic acid were not useful predictors of methotrexate-induced hepatotoxicity. The aminopyrine breath test was abnormal in approximately half the patients with hepatotoxicity but showed poor specificity. Noninvasive methods remain inferior to biopsy for the detection of mild to moderate methotrexate-induced hepatotoxicity in patients with rheumatoid arthritis.

Adult↗
PubMed1993

Enrichment for metallothionein does not confer resistance to cisplatin in transfected NIH/3T3 cells.

Evidence has been presented both that metallothionein does and does not produce resistance to cisplatin. The metallothionein-enriched cells described in most previous studies have been selected for resistance to heavy metals, such as cadmium, or have been maintained in a medium enriched for the metals. Exposure to toxic metals could alter the cells in many ways. This report addresses the effect of metallothionein content alone, independent of exposure to metals, on cellular resistance to cisplatin. The toxicity of cisplatin was compared in NIH/3T3 cells that vary in their content of metallothionein as a consequence of transfection with a plasmid that results in the constitutive expression of metallothionein. The plasmid contains the bovine papillomavirus genome and the mouse metallothionein-I gene; it is driven by a glucose-regulated protein of 78 kD. Control cells were transfected with a similar plasmid in which the coding sequences for metallothionein were inverted and separated from the promoter, thereby abolishing expression. Expression of metallothionein required neither selection nor maintenance of cells in the presence of heavy metals. Despite large differences between the two types of cells in their cellular content of metallothionein and in their resistance to the toxicity of cadmium, no differences in resistance to cisplatin were observed.

3T3 Cells↗
PubMed1993

Distribution of gallium-67 in normal and hypotransferrinemic tumor-bearing mice.

The mechanism by which 67Ga accumulates in tumors is controversial. The most popular theory is that 67Ga binds to transferrin and gains access to cells by the transferrin receptor. However, substantial evidence suggests that uptake of 67Ga may not be universally mediated by transferrin in tumors. To determine whether transferrin is required for uptake of 67Ga in vivo, we compared the uptake of 67Ga by two types of implanted tumors and by normal tissues in normal and severely hypotransferrinemic strains of Balb/C mice. One type of tumor was strongly gallium-avid in normal mice; the other was not. Uptake of 67Ga by normal soft tissues was markedly less in hypotransferrinemic than in normal mice. Uptake of 67Ga by bone was equivalent in the two types of mice. For the more gallium-avid tumor, uptake of 67Ga was similar and the ratio of tumor-to-background activity was substantially higher in the hypotransferrinemic than in the normal mice. For the less gallium-avid tumor, uptake was significantly less in hypotransferrinemic than in normal mice. These data suggest that uptake of 67Ga by bone and by some tumors may be a transferrin-independent process.

Animals↗
PubMed1993

Cerebrovascular accident associated with dipyridamole thallium-201 myocardial imaging: case report.

A patient with known aortoiliac occlusive disease and hypertension suffered a cerebrovascular accident 6.5 min after the administration of intravenous dipyridamole during a 201Tl myocardial study. Despite aminophylline administration, the patient developed a completed stroke. The mechanism most likely responsible for precipitating this patient's stroke is dipyridamole-induced vascular steal. Although dipyridamole-201Tl myocardial imaging is relatively free of major complications, the morbidity and mortality associated with a cerebrovascular accident is significant. The possibility of precipitating a cerebrovascular accident during dipyridamole-201Tl imaging should be considered in all patients with significant risk factors for stroke before performing a dipyridamole cardiac study.

Cerebrovascular Disorders↗
PubMed1993

Enthesopathy of the patellar tendon insertion associated with isotretinoin therapy.

A 99mTc-MDP bone scan performed on a 34-yr-old female for suspected osteomyelitis of the proximal tibia revealed focally increased activity in both tibial tuberosities due to enthesopathies secondary to chronic isotretinoin therapy. Physicians should be aware that isotretinoin therapy can cause abnormal bone scans and not mistake these abnormalities for other diseases such as osteomyelitis. Second, bone scans may be helpful in diagnosing and following isotretinoin bone toxicity.

Adult↗
PubMed1992

Uptake of cadmium is diminished in transfected mouse NIH/3T3 cells enriched for metallothionein.

To determine the relationship between cellular uptake of cadmium and content of metallothionein, we measured uptake of 109Cd in cells that differed in content of metallothionein (MT). MT cells were derived from NIH/3T3 cells by transfection with a plasmid containing the genome of bovine papilloma virus and the mouse metallothionein-I gene, driven by the promotor for the glucose-regulated protein of 78 kDa. Control cells were similarly transfected with bovine papilloma virus-based plasmids with the gene for metallothionein inverted and thus separated from the promoter (TM), or deleted, along with the promoter (BPA). The number of copies of bovine papilloma virus-based plasmids was similar in MT, TM, and BPA cells, approximately 100 per cell. MT cells were more than 10 times more resistant to the lethal effect of cadmium than were the control cells. Synthesis of metallothionein was 15-fold greater in the MT cells than in the TM or BPA cells. The uptake of 109Cd by the cells enriched in metallothionein was 4-fold less than by the control cells. These data suggest that an increased content of metallothionein may protect some cells from the toxic effects of cadmium, in part, by diminishing uptake of the metal.

3T3 Cells↗
PubMed1992

The use of computer-assisted diagnosis in cardiac-perfusion nuclear medicine studies: a review.

The use of computer-assisted diagnosis has become widespread in cardiac nuclear medicine. Quantitative programs are commercially available for ventriculography, phase analysis, and thallium 201 perfusion studies. The goal of these programs is to eliminate interobserver variability by objectively analyzing the studies without causing a loss of accuracy. In addition, by using quantitative data not apparent on visual inspection, some programs attempt to increase sensitivity for disease above that possible by the visual reading of images. Programs that analyze perfusion studies to detect coronary artery disease have received the most interest. Results have varied, but sensitivities as high as 95% have been reported. This review discusses the techniques of computer-assisted diagnosis for thallium 201 myocardial-perfusion studies. The circumferential and washout profile methods are discussed in detail.

Animals↗
PubMed1992

Review of convergent beam tomography in single photon emission computed tomography.

Investigation of convergent-beam single photon emission computed tomography (SPECT) is actively being pursued to evaluate its clinical potentials. Fan-beam, cone-beam, pin-hole and astigmatic collimators are being used with rotating gamma cameras having large crystal areas, to increase the sensitivity for emission and transmission computed tomography of small organs such as the thyroid, brain or heart. With new multi-detector SPECT systems, convergent-beam geometry offers the ability to simultaneously obtain emission and transmission data necessary to quantify uptake of radiopharmaceutical distributions in the heart. The development of convergent-beam geometry in SPECT requires the integration of hardware and software. In considering hardware, the optimum detector system for cone-beam tomography is a system that satisfies the data sufficiency condition for which the scanning trajectory intersects any plane passing through the reconstructed region of interest. However, the major development of algorithms has been for the data insufficient case of single planar orbit acquisitions. The development of these algorithms have made possible the preliminary evaluation of this technology and the imaging of brain and heart are showing significant potential for the clinical application of cone-beam tomography. Presently, significant research activity is pursuing the development of algorithms for data acquisitions that satisfy the data sufficiency condition and that can be implemented easily and inexpensively on clinical SPECT systems.

Brain↗
PubMed1992

Embolization of hepatic arteriovenous malformations using radiolabeled and nonradiolabeled polyvinyl alcohol sponge in a patient with hereditary hemorrhagic telangiectasia: case report.

Polyvinyl alcohol sponge (PVA) radiolabeled with 99mTc-sulfur colloid was used to evaluate a large hepatic arteriovenous malformation (AVM) in a 71-yr-old white female prior to embolization. The patient had hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu) with severe left-to-right shunting through the hepatic AVM which resulted in high-output congestive heart failure. The patient also had severe pulmonary hypertension. Scintigraphic imaging of the embolized radiolabeled PVA particles allowed us to be certain that the particles did not flow through the liver and inadvertently embolize the lungs; with the patient's already poor pulmonary status, embolization could have been fatal.

Aged↗
PubMed1991

Physiological and pharmacological interventions in radionuclide imaging of the tubular gastrointestinal tract.

Radionuclide studies of the gastrointestinal tract (GI) are used to measure GI function and to detect anatomic lesions such as Meckel's diverticuli. A variety of physiological and pharmacological interventions have been applied to both types of studies to gain a better understanding of GI function and to improve detection of disease. This article will review interventions useful in imaging the tubular GI tract. Discussed are the measurement of GI motility and function by gastric emptying and imaging studies for GI bleeding including the Meckel's scan. Interventions involving the hepatobiliary system are covered elsewhere in this issue.

Cimetidine↗
PubMed1991

Cone beam tomography of the heart using single-photon emission-computed tomography.

The authors evaluated cone beam single-photon emission-computed tomography (SPECT) of the heart. A new cone beam reconstruction algorithm was used to reconstruct data collected from "short scan" acquisitions (of slightly more than 180 degrees) of a detector anteriorally traversing a noncircular orbit. The less than 360 degrees acquisition was used to minimize the attenuation artifacts that result from reconstructing posterior projections of 201T1 emissions from the heart. The algorithm includes a new method for reconstructing truncated projections of background tissue activity that eliminates reconstruction ring artifacts. Phantom and patient results are presented which compare a high-resolution cone beam collimator (50-cm focal length; 6.0-mm full width at half maximum [FWHM] at 10 cm) to a low-energy general purpose (LEGP) parallel hole collimator (8.2-mm FWHM at 10 cm) which is 1.33 times more sensitive. The cone beam tomographic results are free of reconstruction artifacts and show improved spatial and contrast resolution over that obtained with the LEGP parallel hole collimator. The limited angular sampling restrictions and truncation problems associated with cone beam tomography do not deter from obtaining diagnostic information. However, even though these preliminary results are encouraging, a thorough clinical study is still needed to investigate the specificity and sensitivity of cone beam tomography.

Algorithms↗
PubMed1991

Radionuclide detection of occult infection: current strategies.

A number of new radionuclide techniques are available for diagnosing infection. These include the radiolabeling of neutrophils and lymphocytes with a variety of chelating agents and isotopes, and the use of antibodies directed against bacteria in the inflammatory exudate. Other new techniques include radiolabeled nanocolloids, chemotactic peptides, and liposomes. This article reviews the evolving role of these techniques in the detection of sites of occult infection.

Animals↗
PubMed1991

Naloxone reverses pattern of obstruction of the distal common bile duct induced by analgesic narcotics in hepatobiliary imaging.

It is widely known that narcotics, such as morphine, cause spasm of the sphincter of Oddi, increasing pressure in the common bile duct. This pharmacologic effect has been applied to hepatobiliary scintigraphy in patients with chronic cholecystitis or cholestasis to reducing the time required for a diagnostic study. However, this feature of narcotics could result in delayed or nonvisualization of the small bowel, simulating a distal common bile duct obstruction, in patients requiring parenteral narcotic analgesics who must undergo hepatobiliary scintigraphy. We report on three patients where administration of intravenous naloxone hydrochloride (Narcan), a narcotic antagonist, was helpful in distinguishing narcotic-induced spasm of the sphincter of Oddi from true obstruction of the common bile duct.

Adult↗