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Biomedical subjects

R Moncada

Publications and source records attributed to R Moncada.

At least 37 records · Page 2Linked to original sources
PubMed1987

Computed tomography of superior vena cava obstruction.

Which imaging procedure is best for the diagnosis of the superior vena cava (SVC) syndrome is subject to considerable debate. Available imaging procedures include the plain chest film, SVC phlebography, scintiangiography, digital phlebography, CT digital phlebography, and CT. In our experience the combined technique of contrast enhanced CT axial images, followed by a CT digital phlebogram, is the most informative, cost-effective, and least invasive method available.

Humans↗
PubMed1987

Catamenial pneumothorax: case report and literature review.

Since the initial case report in 1958, 69 cases of catamenial pneumothorax have appeared in English-language literature. Despite the extensive case material, the pathogenesis has not been fully elucidated. Herein an additional case is reported utilizing computed tomography (CT) to search for intrathoracic endometrial implants. The four major pathogenetic theories include passage of air from the genital tract via diaphragmatic defects, spontaneous rupture of subpleural blebs, intrathoracic endometriosis, and prostaglandin-induced bronchiolar constriction resulting in alveolar rupture. Evidence for and against each theory is presented.

Adult↗
PubMed1987

The role of percutaneous drainage of pancreatic abscesses.

Pancreatic abscess remains the most lethal form of intra-abdominal abscess despite a wide variety of operative approaches that have been advocated for its control. Mortality is frequent, and recurrent abscesses after operative drainage are common. Death often results from ongoing uncontrolled sepsis. The role of percutaneous drainage (PCD) of pancreatic abscesses is controversial. Recent experience with five patients who had pancreatic abscess and in whom a combination of operative drainage and PCD proved instrumental in survival leads the authors to recommend the consideration of both forms of drainage dependent upon the circumstances. Specifically, indications for PCD may include the following: use as a temporizing measure prior to celiotomy in a critically ill patient; use in postoperative patients who have recurrent abscesses and in whom the presence of dense inflammation precludes safe evacuation of pus; and use in the patient who has known portal hypertension and in whom massive bleeding is likely to result from celiotomy and abscess drainage.

Abdomen↗
PubMed1986

Radiologic diagnosis of an intra-abdominal abscess. Do multiple tests help?

A review was made of the charts of 94 patients who underwent ultrasonography (US), computed tomography (CT), and gallium citrate Ga 67 (Gall) scan to rule out intra-abdominal abscesses. Of all the clinical and laboratory data, only the presence of pain and tenderness differentiated patients with and without abscesses. A review of radiologic data showed that CT was superior to US, and that US was superior to Gall scan with regard to sensitivity, specificity, accuracy, and positive and negative predictive values. When multiple radiologic tests were performed, results agreed in 72% of cases; therefore, the additional tests were essentially redundant. When radiologic test results disagreed, accuracy rates were CT, 0.86; US, 0.00; and Gall scan, 0.44. These findings suggest that, except to rule out pelvic abscesses in the presence of pelvic inflammatory disease, CT is usually the only special radiologic test that should be performed to localize a suspected intra-abdominal abscess.

Abdomen↗
PubMed1986

Diagnosis of intrapericardial tumor in an infant by two-dimensional echocardiography.

Two-dimensional echocardiography is a useful noninvasive tool for diagnosing intrapericardial tumors as a cause of respiratory distress or abnormal cardiomediastinal shadow on chest x-ray. Early recognition of these tumors within the pericardium is important since surgical removal is often curative. Cardiac cineangiography is unnecessary to delineate further the tumor and should be reserved for those in which associated intracardiac defects are suspected.

Cysts↗
PubMed1986

Contrast media-induced chromosomal damage in human lymphocyte cultures.

Ionic (diatrizoate, ioxaglate) and nonionic (iohexol, iosimide, iopromide, and iotrolan) contrast media (CM) were evaluated for their cytogenetic effects in lymphocytes. Heparinized blood was mixed with culture medium RPMI-1640 supplemented with phytohemagglutinin, fetal calf serum, and antibiotics. Plastic tubes containing blood samples were incubated at 37 degrees C in 5% CO2 humidified air for 48 hours. To these cultures, increasing amounts of CM were added and cells incubated for an additional 24 hours. After this exposure, red blood cells were lysed with hypotonic KC1, lymphocyte smears fixed on glass slides and stained with May-Grünwald Giemsa. Chromosomal damage was analyzed by a micronucleus test. All CM tested induced micronuclei in lymphocytes quite significantly (P less than .001) when compared with the frequency of micronuclei in controls. These observations on the genotoxic potential of nonionic CM suggest that factors other than ionic composition and osmolality are involved in clastogenesis; further studies are needed to establish the molecular mechanisms in CM induced chromosomal damage.

Cell Nucleus↗
PubMed1986

Nonionic contrast medium: effects on blood coagulation and complement activation in vitro.

A nonionic contrast medium was evaluated in vitro for its effects on coagulation and complement activation in comparison to a low osmolal contrast agent. In clotting assays each contrast medium was mixed with blood and clotting parameters were analyzed by using a thromboelastographic machine. Platelet function was studied by incubating platelet-rich plasma with individual contrast medium, and the subsequent challenge of a platelet aggregating agent. Complement activation was assessed by the hydrolysis of C3 protein into C3c fragment in contrast medium-incubated serum. Immunoelectrophoresis was used to detect C3c protein. Both the nonionic contrast medium and the low osmolal contrast agent acted as anticoagulant and antiplatelet agents, however, results with the low osmolal contrast agent were more pronounced compared to the nonionic contrast medium. Even at nonphysiologic concentration of contrast medium, no significant conversion at C3 to C3c was seen. Since these two agents caused hypocoagulable states in vitro, it is likely that patients with thrombocytopenia, severe liver disease and with clotting factor deficiencies may present hemostatic complications during angiographic procedures.

Blood Coagulation↗
PubMed1986

Multimodality approach to pericardial imaging.

In this chapter, three modalities--computed tomography, nuclear magnetic resonance imaging, and echocardiography--have been discussed. Each of these techniques offers unique advantages in the diagnosis of pericardial disease. Although echocardiography is the least expensive, most sensitive, and least invasive technique for the identification of pericardial effusion, false-positive and negative studies may be encountered. These are often resolved with the use of computed tomography and may be resolved with magnetic resonance imaging. Plain film radiography still has the advantage of identifying pericardial calcifications and will suggest the diagnosis of large pleural effusions at low cost and radiation dose. Exquisite portrayal of cross section anatomy using CT will aid in the diagnosis of multiple small tumor deposits and will clearly identify pericardial thickening. The value of magnetic resonance imaging awaits carefully controlled blinded studies, but its role in characterization of the content of pericardial effusions appears especially promising.

Cardiomyopathy, Restrictive↗
PubMed1985

Normal excretory urography in patients with primary kidney neoplasms.

The records of 65 consecutive patients discharged from the hospital with a diagnosis of primary parenchymal neoplasm of the kidney were reviewed. Four of the 65 patients had neoplasms which were not detected by excretory urography. The 4 undetected lesions included 3 renal cell carcinomas and 1 oncocytoma. All of these lesions projected from the anterior or posterior surface of the kidney, and all 4 were clearly demonstrated by computed tomography. Normal findings on an excretory urogram do not completely exclude a neoplasm of the kidney. When there is strong clinical suspicion of a renal neoplasm, computed tomography should be the initial examination or should be done even if the urogram has shown normal findings.

Adenoma↗
PubMed1985

Complement abnormalities during contrast media procedures.

Complement changes following the administration of the two most commonly used intravascular contrast media (CM) diatrizoate and iothalmate were studied in 26 patients by measuring complement component C3 levels and the total hemolytic function. Blood from these patients was obtained in plastic tubes containing 10 mM ethylene diamine tetra-acetic acid (EDTA) prior to and 15 min after contrast media infusion. In thirteen patients who received iothalamate a 28% drop in C3 concentration and a 19% change in total hemolytic complement was seen. In the second group of thirteen patients diatrizoate caused a 20% C3 decrease and a 15% reduction in total hemolytic complement. Since iothalamate is a hyperosmolar and hyperviscous solution compared to diatrizoate, it is likely that these factors are responsible for changes in complement level which may present potential risk to patients with depressed immunologic status. This study suggests that screening of patients for their total complement profile may provide useful information in minimizing adverse reactions to contrast material.

Adult↗
PubMed1985

Ultrastructural changes in rat aortic endothelium during contrast media infusion.

A rat model was employed to investigate contrast media (CM) induced ultrastructural changes in the vascular endothelium. Ionic contrast materials such as Renografin-76 (diatrizoate meglumine diatrizoate sodium), MD-76 (diatrizoate meglumine diatrizoate sodium), and Angiovist (meglumine diatrizoate) were injected into the femoral vein of anesthetized male Wistar rats (240-260 g) and allowed to circulate. Control animals were similarly injected with equiosmolar sucrose and physiologic saline. The thorax was opened 15 minutes, 1 hour, and 4 hours postinjection and cardiac perfusion performed using Karnovsky's fixative; the thoracic aorta was then surgically removed, and processed for transmission electron microscopy. All CM produced shrinkage in cell cytoplasm and nuclear structures thereby causing distortions in cell morphology. In control tissues, however, no such ultrastructural damages were noted. Within 15 minutes of CM infusion, electron dense granules were seen on the luminal surface of endothelial cells, in pinocytotic vesicles, as well as in the gap junctions between cells. These observations indicate that contrast media intake occurs via vesicular transport, and through the cell junction.

Animals↗
PubMed1984

Molecular markers of contrast media-induced adverse reactions.

Currently used routine laboratory screening methods are not reliable in the prediction of contrast media-related adverse reactions. Cost-effective laboratory methods for various molecular markers of pathophysiologic activation have now become available. In vitro activation tests in high-risk patients may prove to be useful in the prediction of contrast-induced activation of various adverse reactions. If prior clinical evaluation of a patient suggests an ongoing pathologic process, profiling of the following molecular markers may prove to be useful and helpful in avoiding contrast-induced adverse reactions: Fibrinopeptide A, platelet factor 4, thromboxane B2, 5-HETE, physiologic inhibitors of proteases, B beta 15-42 related peptides, bradykinin/kininogen, and anaphylactozins. In patients suspected of reacting to contrast agents, a small dose of 1 to 5 ml can be injected as a bolus and molecular marker profiling on blood drawn after the infusion may prove to be useful screening tests. Additional clinical studies are needed to prove this. However, this screening test should be performed with extreme caution, since some of the patients are known to react to as little as 1 ml dose. The safety of newly developed nonionic contrast agents can be readily assessed by profiling various molecular markers of adverse reactions, which provide a more reliable and quantitative assessment of contrast-induced adverse reactions. Based on molecular marker profiling, various prophylactic agents can be given to high-risk patients to avoid contrast-induced adverse reactions.

Angiocardiography↗
PubMed1984

Evaluation of superior vena cava syndrome by axial CT and CT phlebography.

Transverse axial computed tomography (CT) has been combined with CT digital phlebography to study nine patients with superior vena cava syndrome. Six were due to malignancy, two were secondary to benign disease, and one was a paraneoplastic manifestation. This combined CT approach successfully identified the abnormal morphology of the superior vena cava, demonstrating external compression, encasement, or intraluminal thrombus in all patients and the collateral venous channels in eight. The efficacy and advantages of this technique are discussed. This technique is a rapid, informative, and cost-effective method for the workup of superior vena cava syndrome. The CT digital phlebogram, however, is not successful in regularly and optimally opacifying the normal superior vena cava because of the limited amount of contrast material, dilution effect of the nonopacified incoming flow from the jugular and azygos veins, and the lack of image enhancement from the CT digital scanograms.

Adenocarcinoma↗
PubMed1984

Intravenous contrast bolus in computed tomography investigation of mass lesion.

Using bolus intravenous contrast (25-75 Renografin 60) and 5-second scanning capability, better definition of vascular anatomy as well as the vascular nature of mass lesions in the chest and abdomen could be demonstrated. The immediate higher concentration of iodine in vessels and organs following initial bolus, improves visualization of these structures dramatically when compared to drip-infusion technique. A description of the technique and examples are shown.

Abdominal Neoplasms↗
PubMed1983

Characterization of cell surface antigens of human mammary epithelial cells with monoclonal antibodies prepared against human milk fat globule.

Hybridomas have been prepared that secrete monoclonal antibodies against three different surface antigens of normal human mammary epithelial cells by fusion of mouse myeloma cells with spleen cells from mice and rats immunized with delipidated human milk fat globules. Using a novel method for molecular weight determination, the three different monoclonal antibodies, BLMRL-HMFG-Mc3, BLMRL-HMFG-McR2, and BLMRL-HMFG-Mc5, were found to identify molecules with apparent molecular weights of 46,000, 70,000, and 400,000 daltons, respectively. The latter is a mucin-like glycoprotein with a high sugar content and has not previously been described as a component of the human milk fat globule or of human mammary epithelial cell membranes. Single-cell quantitation of binding of monoclonal BLMRL-HMFG-Mc5 to three breast tumor cell lines using a Microscope Spectrum Analyzer and indirect immunofluorescence revealed a heterogeneous expression. Further, using a competitive radioimmunoassay, it was found that breast tumor cell lines differed by at least 10-fold in the 400,000-molecular-weight antigen content. None of the three antigens are detectable on several nonbreast cell lines, including normal breast fibroblasts.

Animals↗
PubMed1983

Chronic stridor in a child: CT diagnosis of pulmonary vascular sling.

A child without chronic stridor and tracheal narrowing was considered to have a primary tracheal abnormality. Computed tomography (CT) identified an aberrant left pulmonary artery originating from the right pulmonary as the cause of the tracheal abnormality. The advantages of CT over conventional studies are discussed.

Child↗