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Biomedical subjects

C Beam

Publications and source records attributed to C Beam.

15 recordsLinked to original sources
PubMed2001

Risk factors for coronary heart disease in men 18 to 39 years of age.

BACKGROUND: Few studies have evaluated the long-term predictive capacity of risk factors for death from coronary heart disease in men younger than 40 years of age. OBJECTIVE: To assess the predictive capacity and discriminatory ability of major coronary risk factors in predicting death from coronary heart disease in young men. DESIGN: Prospective cohort study with 20 years of follow-up. SETTING: 84 companies in the Chicago area that participated in the Chicago Heart Association Detection Project in Industry (1967-1973). PARTICIPANTS: 11 016 men 18 to 39 years of age (mean age, 29.7 years) at baseline were the primary focus of this report; 8955 men 40 to 59 years of age at baseline served as a reference group. MEASUREMENTS: The main end point was death from coronary heart disease. RESULTS: All major risk factors-age, serum cholesterol level, systolic blood pressure, and cigarette smoking-were significantly associated with death from coronary heart disease over 20 years in young men. Relative risks for the major risk factors were of generally similar magnitude in young and middle-aged men. Receiver-operating characteristic curves for the best predictive model yielded an area under the curve of 0.82, indicating that standard risk factors were highly predictive of long-term outcome in young men. CONCLUSIONS: Major coronary disease risk factors, many of which are modifiable, are strong contributors to prediction of future risk, even in young men. These data may help in formulating appropriate strategies to identify young men at heightened risk for death from coronary heart disease in later adulthood.

Adolescent↗
PubMed1993

Temporal lobe hypometabolism on PET: predictor of seizure control after temporal lobectomy.

To investigate the relationship of temporal lobe hypometabolism demonstrated on PET to surgical outcome and underlying pathology, we reviewed 30 consecutive epilepsy patients who underwent interictal PET studies with 18F fluorodeoxyglucose before temporal lobectomy. Two interpreters blindly reviewed the PET studies and graded them for degree, extent, and location of temporal lobe hypometabolism. Pathologic analysis of en bloc resected tissue showed mesial temporal sclerosis (n = 22), astrocytoma (n = 2), and no pathologic diagnosis (n = 6). Outcome (24 to 40 months' follow-up) was rated as seizure-free (21 patients), significantly improved (five patients), and not significantly improved (four patients). Both the degree and extent of the temporal lobe hypometabolism demonstrated on PET were strongly associated with subsequent seizure control. Pathologic findings, however, did not correlate with degree of PET hypometabolism or subsequent outcome. These data demonstrate that in patients judged to have temporal lobe epilepsy, the presence of temporal lobe hypometabolism is associated with a positive outcome after ipsilateral temporal lobectomy.

Adolescent↗
PubMed1993

Contrast material for combined abdominal and pelvic CT: can cost be reduced by increasing the concentration and decreasing the volume?

OBJECTIVE: The purpose of this study was to determine if enhancement provided by a smaller volume of a more concentrated nonionic contrast agent is equivalent to that provided by a larger volume of a less concentrated nonionic agent on dynamic, incremental abdominal and pelvic CT. SUBJECTS AND METHODS: During a 4-month period, 168 patients undergoing dynamic incremental abdominal and pelvic CT received 150 ml iopamidol-300 (45 g iodine). During the following 4 months, 119 patients received 125 ml ioversol-320 (40 g iodine). The same automated injector and scanning parameters were used for both groups. Absolute enhancement of the liver at three levels and of abdominal and pelvic vessels was calculated and analyzed by using Student's t-test. RESULTS: Arterial and venous enhancement in the upper part of the abdomen, at the level of the iliac crest, or in the pelvis was not significantly different with the two contrast agents. Both ioversol and iopamidol provided the same mean enhancement of the hepatic parenchyma at the level of the hepatic veins (45 H) and at the level of the portal vein (49 H). At the level of the gallbladder fossa, enhancement of liver parenchyma with the two contrast agents was significantly different (p = .04): mean enhancement was 45 H for iopamidol and 42 H for ioversol. A retrospective analysis of the liver enhancement profiles from 50 randomly selected patients from each group showed no significant difference in parenchymal enhancement. CONCLUSION: For dynamic abdominal and pelvic CT, no statistically significant difference was found between the mean enhancement of the liver and abdominal vessels after administration of 125 ml of ioversol-320 and that after administration of 150 ml of iopamidol-300. Therefore, 125 ml of ioversol-320 can be used instead of 150 ml of iopamidol-300 without compromising image quality. At current prices, this will result in savings of approximately 18% per patient.

Abdomen↗
PubMed1992

Adrenal gland enlargement in major depression. A computed tomographic study.

To determine whether the well-documented hyperactivity of the hypothalamic-pituitary-adrenal axis in depressed patients includes adrenal gland hypertrophy, adrenal gland size was evaluated by computed tomography. Assessments consisted of (1) global ratings by two radiologists ignorant of the diagnostic identity of the subjects and (2) calculation of adrenal volume. Of the 38 patients with major depression, 12 were rated as exhibiting adrenal hypertrophy. Adrenal volumes in the depressed patients were significantly increased when compared with those of normal controls. Adrenal gland size was not correlated with dexamethasone suppression test results, patient age, duration of the depressive episode, or depression severity. These results are concordant with the hypothesis that chronic corticotropin hypersecretion in depression results in adrenocortical hypertrophy. Adrenal gland enlargement may be a measure of cumulative lifetime depression.

Adrenal Glands↗
PubMed1991

Imaging of the renal arteries: value of MR angiography.

We compared the efficacy of MR angiography with that of conventional angiography for visualizing the renal arteries and detecting renovascular disease. Thirty-three MR angiographic studies, consisting of axial two-dimensional (2-D) phase-contrast, coronal 2-D phase-contrast, and coronal 2-D time-of-flight acquisitions, were performed within 48 hr of conventional arteriography. The studies were done to evaluate possible renovascular hypertension (n = 25) or potential donor nephrectomy (n = 8). The three MR image sets were interpreted independently, in random order by three observers, with regard to the number of renal arteries, degree of vessel visualization, arteriovenous overlap, and presence of renovascular disease. A fourth interpretation was based on the combined axial and coronal phase-contrast image sets. Evaluation was limited to the proximal 35 mm of each renal artery. Renal artery visualization and detection of renovascular disease were more complete with coronal phase-contrast (80% sensitivity, 91% specificity) than with time-of-flight (53% sensitivity, 97% specificity) images. Combined axial and coronal phase-contrast images permitted visualization of the proximal 35 mm of all dominant renal arteries and detection of 13 of 15 stenoses (87% sensitivity, 97% specificity). Our data suggest that biplanar MR angiography has considerable potential as a noninvasive screening technique for the evaluation of renovascular disease.

Angiography↗
PubMed1990

Soft-tissue sarcomas: detection of metabolic heterogeneity with P-31 MR spectroscopy.

Regional variations in metabolic parameters derived with multivoxel, localized phosphorus-31 magnetic resonance (MR) spectroscopy in spontaneous human-soft-tissue sarcomas were compared with variations in the same parameters in normal human legs. In addition, multivoxel P-31 MR spectroscopy of transplanted rodent sarcomas and microelectrode measurement of pH and PO2 in several locations within them were performed, and, when appropriate, results were compared with the clinical data. Striking voxel-voxel variability in parameters derived with P-31 spectroscopy was found in tumors, with less marked variability seen in normal legs. In the rodent tumors, spatial variations also were found in pH and PO2 measured by means of microelectrodes. These data are consistent with the results of regional measurements in tumors by means of other methods and suggest that clinical MR spectroscopic studies of tumors may need to consider the variability within malignant lesions.

Animals↗
PubMedDate not supplied

Cardiac ejection fraction: phantom study comparing cine MR imaging, radionuclide blood pool imaging, and ventriculography.

The accuracy and reproducibility of cardiac ejection fraction (EF) measurements based on cine magnetic resonance (MR) imaging, radionuclide multigated acquisition (MUGA) blood pool imaging, and angiographic ventriculography were evaluated by comparing them with a volumetrically determined standard. A biventricular, compliant, fluid-filled heart phantom was developed to mimic normal cardiac anatomy and physiology. Ventricular EFs were measured with cine MR imaging by summation of nine contiguous 10-mm-thick sections in short and long axis, with single-plane ventriculography, and with MUGA. Three measurements were performed with each modality for each of three EFs. Ventriculography was least accurate, with average relative errors ranging from 7.9% for the largest EF to 60.1% for the smallest. Cine MR was most accurate, with average relative errors ranging from 4.4% to 8.5%. MUGA EF measurements showed good correlation, with average relative errors ranging from 7.1% to 22.4%. Comparison of the error variances for the three modalities with the F test revealed that MR and MUGA EF measurements were significantly more accurate than those based on ventriculography (P less than .01). No significant difference was demonstrated between the accuracy of short- and long-axis cine MR acquisitions.

Gated Blood-Pool Imaging↗
PubMedDate not supplied

Ozonation of DNA forms adducts: a 32P-DNA labeling and thin-layer chromatography technique to measure DNA environmental biomarkers.

Little direct documented evidence of ozone's genotoxicity exists. Deoxyribonucleic acid (DNA) adducts are produced by environmental toxic agents, including ozone. We have described a modified thin-layer chromatography (TLC) technique that can assess adduct formation as a biomarker of ozone injury. This requires 32P-labeling DNA, digestion of deoxynucleotides (dNMPs), and separation in two-dimensional PEI-cellulose TLC. We have applied this technique to control DNAs, to control DNA in solution exposed to acute ambient ozone, and to control DNA exposed to acute bubbled-through ozone (2 ppm for 24 h). We detected stable DNA adducts, including hydroxymethyluracil (HMU), thymine glycol (TG), 8-hydroxyguanine (8-OHG), and demonstrated, as yet, unidentified adducts that may serve as a "fingerprint" pattern of DNA adduction. This technique quantifies low-molecular-mass DNA adducts, both in vivo and in vitro, with potential applications to environmental toxicology.

Animals↗
PubMedDate not supplied

Serial FDG-PET studies in the prediction of survival in patients with primary brain tumors.

OBJECTIVE: This study examines the changes in tumor [18F]fluoro-2-deoxyglucose (FDG) uptake on serial FDG-PET studies and the ability of serial FDG-PET studies to predict survival in patients with treated and untreated primary brain tumors. MATERIALS AND METHODS: The study population included 20 patients with primary brain tumors. Changes in FDG uptake over time were visually assessed and correlated with clinical course and survival. RESULTS: Although little change in FDG uptake was noted for individual patients, high average FDG uptake (greater than or equal to gray matter) on serial studies was associated with shorter survival. Patients with persistently low FDG uptake (less than gray matter) survived significantly longer than patients with persistently high FDG uptake (p = 0.007). CONCLUSION: Serial evaluation of metabolic activity with PET may provide more accurate prognostic information than a single FDG uptake determination in patients with primary brain tumors.

Adult↗