PubMed Health⌕ Search

Biomedical subjects

M Rifkin

Publications and source records attributed to M Rifkin.

At least 19 recordsLinked to original sources
PubMed2000

Efficacy and safety of mangafodipir trisodium (MnDPDP) injection for hepatic MRI in adults: results of the U.S. Multicenter phase III clinical trials. Efficacy of early imaging.

The efficacy of contrast-enhanced magnetic resonance imaging (MRI) for detecting and characterizing, or excluding, hepatic masses was assessed in 404 patients, following the intravenous administration of mangafodipir trisodium (MnDPDP) injection, a hepatic MRI contrast agent. An initial contrast-enhanced computed tomography (CT) examination was followed by unenhanced MRI, injection of MnDPDP (5 micromol/kg IV), and enhanced MRI at 15 minutes post injection. Agreement of the radiologic diagnoses with the patients' final diagnoses was higher for enhanced MRI and for the combined unenhanced and enhanced MRI evaluations than for unenhanced MRI alone or enhanced CT using the clinical diagnosis as the gold standard. Mangafodipir-enhanced MRI uniquely provided additional diagnostic information in 48% of the patients, and patient management was consequently altered in 6% of the patients. MnDPDP-enhanced MRI was comparable or superior to unenhanced MRI and enhanced CT for the detection, classification, and diagnosis of focal liver lesions in patients with known or suspected focal liver disease.

Adult↗
PubMed1996

Increased bcl-2 protein levels in prostatic adenocarcinomas are not associated with rearrangements in the 2.8 kb major breakpoint region or with p53 protein accumulation.

bcl-2, an inhibitor of programmed cell death (apoptosis), is present in high levels in a subset of prostatic adenocarcinomas. In this study, 42 prostatic adenocarcinomas were analyzed to determine whether increased bcl-2 levels are associated with rearrangements in the 2.8-kb major breakpoint region, an association known to occur in certain follicular lymphomas featuring a t(14:18) translocation. Immunostaining for bcl-2 and p53 proteins was performed on formalin-fixed, paraffin-embedded tumor specimens using murine anti-human bcl-2 and p53 monoclonal antibodies in all 42 cases. Genomic DNA from paired frozen samples of each tumor was subjected to digestion with HindIII and EcoRI and the products analyzed on a Southern blot with a 2.8-kb-digoxigenin-labeled major breakpoint region probe. Comparisons between groups were evaluated with the Fisher exact test. Diffuse, strong cytoplasmic immunoreactivity for bcl-2 was present in the epithelial cells of tumor glands in 16 of 42 cases (38%), including 8 of 19 low grade (Gleason score 6 and below) and 8 of 23 high grade (Gleason score 7 and above) prostatic adenocarcinoma. Southern blotting demonstrated a normal 2.8-kb germline DNA fragment in every case, with no evidence of rearrangement. Nuclear p53 staining was present in 10 of 24 high grade and 0 of 18 low grade tumors (P < 0.001). Only four cases exhibited positivity for both bcl-2 and p53, and there was no association of bcl-2 positivity with co-expression of the p53 protein (P = 0.58). We conclude that aberrations in the function of either bcl-2 or p53 could possibly modify the apoptotic pathway resulting in the extended survival of tumor cells. Also, increased bcl-2 levels in prostatic adenocarcinomas occur in the absence of detectable rearrangements in the major breakpoint region.

Adenocarcinoma↗
PubMed1992

Application of DNA amplification to pneumocystosis: presence of serum Pneumocystis carinii DNA during human and experimentally induced Pneumocystis carinii pneumonia.

Pneumocystis carinii pneumonia is a leading cause of morbidity and mortality in patients with the acquired immunodeficiency syndrome (AIDS). Much remains unknown about the basic biology of P. carinii and studies of this infection have been hampered by the lack of cultivation methods. We developed a sensitive and specific assay for P. carinii by utilizing DNA amplification of the P. carinii dihydrofolate reductase (DHFR) gene. By this method, P. carinii DNA was detected in the lungs of rats with experimentally induced P. carinii pneumonia 2 wk before the onset of histopathological changes. DNA amplification analysis of serum demonstrated that by 10 wk of corticosteroid treatment, 12 of 12 (100%) infected rats had circulating DHFR DNA. P. carinii DHFR DNA also was detected in the serum of patients with AIDS and active P. carinii pneumonia (12 of 14 sera collected prospectively). Patients with advanced AIDS but without a history of P. carinii pneumonia were negative by this assay (0 of 6 sera examined). Serum polymerase chain reaction may facilitate investigations into the natural history and epidemiology of P. carinii infection, provide insight into the pathogenesis of parasite dissemination, and offer a useful, noninvasive diagnostic test for the detection of human pneumocystosis.

Acquired Immunodeficiency Syndrome↗
PubMed1990

MR imaging of pulmonary parenchyma and emboli by paramagnetic and superparamagnetic contrast agents.

Using experimentally induced pulmonary emboli in an animal model, three intravenously administered contrast agents, Gd-DTPA-albumin microspheres (8-15 microns, 0.2 M particles/mg protein, 39-106 micrograms Gd/mg, 50 mg/ml), Gd-DTPA-liposomes (15-30 microns, 130 micrograms/mg lipid, 6 mg Gd/ml) and superparamagnetic ferrosome, (60 nm, 100 mM iron and 20 mg lipid/ml) were examined for MR imaging. Gd-DTPA entrapped in lung capillaries did not enhance the signal intensity of lung parenchyma, but liposomes (5 ml) served as better Gd-DTPA carriers and increased the parenchymal signal intensity by up to a factor of 2.3. However, neither agent improved delineation of pulmonary emboli. Ferrosome decreased the intensity of lung parenchyma, improving detectability of pulmonary emboli by several factors.

Animals↗
PubMed1989

Abdominal abscesses: ultrasound guided percutaneous therapy.

Percutaneous abscess drainage using cross-sectional imaging has become an accepted and important clinical tool. Most previous reports have emphasized the importance of CT as the primary study for guidance. Ultrasound has been suggested as a complementary as opposed to a primary guiding modality. This has been stated because of the complications that may result from possible incomplete visualization of intervening structures and demonstration of incomplete emptying. Our data of 91 abscess drainages in 66 patients treated with percutaneous abscess drainage and performed exclusively with ultrasound guidance, suggest that ultrasound is at least as useful and as accurate a tool for drainage as any other modality. An overall success of 89% was obtained and severe complications in general were less than previously reported utilizing CT. Out data suggest that ultrasound is certainly as useful a guiding technique for cross-sectional imaging when needed for localization and drainage of abscesses.

Abscess↗
PubMed1988

Assessment of lung water by magnetic resonance in three types of pulmonary edema.

Pulmonary edema was produced in nine mongrel dogs by: (a) saline lavage; (b) intravenous injection of oleic acid; and (c) intravenous injection of propranolol followed by ureteral ligation. The resulting effect could be characterized by varying the protein concentration in the pulmonary edema fluid. After induction, all dogs were killed and 20 samples from each passively deflated lung were obtained. Proton T1 and T2 values were measured on a Praxis II NMR spectrometer operated at 10.7 MHz and 37 degrees C. The water content of all samples was determined gravimetrically. Correlation between T1 or T2 measured in vitro and the ratio of wet to dry weight was highly significant (r greater than 0.95, P less than 0.001) in each pathological state. Regression curves indicate that although all three types of pulmonary edema can be characterized by slightly different slopes, the differences are statistically insignificant. Moreover, the slopes of previous studies, when recast in the same format, are very similar to our findings despite the use of different magnetic field strengths and different animal models. This study indicates that quantitation of pulmonary edema is possible, but in vitro measurements do not give useful information for characterizing the etiology of pulmonary edema.

Animals↗