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1.
J Magn Reson ; 139(1): 81-9, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10388587

ABSTRACT

A novel three-axis gradient set and RF resonator for orthopedic MRI has been designed and constructed. The set is openable and may be wrapped around injured joints. The design methodology used was the minimization of magnetic field spherical harmonics by simulated annealing. Splitting of the longitudinal coil presents the major design challenge to a fully openable gradient set and in order to efficiently design such coils, we have developed a new fast algorithm for determining the magnetic field spherical harmonics generated by an arc of multiturn wire. The algorithm allows a realistic impression of the effect of split longitudinal designs. A prototype set was constructed based on the new designs and tested in a 2-T clinical research system. The set generated 12 mT/m/A with a linear region of 12 cm and a switching time of 100 micros, conforming closely with theoretical predictions. Preliminary images from the set are presented.


Subject(s)
Knee Joint/anatomy & histology , Magnetic Resonance Imaging/instrumentation , Algorithms , Humans , Magnetic Resonance Imaging/methods , Orthopedics
2.
J Clin Oncol ; 16(9): 3129-36, 1998 Sep.
Article in English | MEDLINE | ID: mdl-9738585

ABSTRACT

PURPOSE: To compare the prognostic impact of tumor angiogenesis factors (vascular endothelial growth factor [VEGF], angiogenin, and basic fibroblast growth factor [bFGF]), tumor proteolysis factors (urokinase-type plasminogen activator [uPA] and plasminogen activator inhibitor-1 [PAI-1]), and conventional tumor markers (stage, grade, and steroid receptors) in early breast cancer. PATIENTS AND METHODS: In the primary clinical study, tumor angiogenesis and other factors were detected in frozen biopsies from 305 primary breast tumors. VEGF expression was assessed by chemiluminescence immunosorbent assay (ICMA); angiogenin, bFGF, uPA, and PAI-1 by enzyme-linked immunosorbent assay (ELISA); and steroid receptors (estrogen receptor [ER] and progesterone receptor [PgR]) by enzyme immunoassay (EIA). In the validating clinical study, another set of 190 node-negative primary breast tumor samples were collected at a separate institution. RESULTS: Univariate analysis of the primary study showed that VEGF levels were positively correlated with recurrence (P < .001). Angiogenin levels were positively correlated with disease relapse (P < .005) for the overall collective group, but not within the node-negative subset. No significant correlations were found between tumor bFGF levels and patient survival. In multivariate regression analysis, the only independent predictors of relapse-free survival (RFS) were VEGF, uPA, and lymph node status. In the validation set, the distribution of VEGF and uPA values were similar to those in the primary study; low expression of both VEGF and uPA identified patients with a < or = 20% likelihood of recurrence within 7 years. CONCLUSION: Separate primary and validating clinical studies concur that tumor VEGF level is the most important prognostic parameter among several markers of tumor angiogenesis and proteolysis.


Subject(s)
Biomarkers, Tumor/metabolism , Breast Neoplasms/blood supply , Neovascularization, Pathologic/metabolism , Plasminogen Activator Inhibitor 1/metabolism , Ribonuclease, Pancreatic , Urokinase-Type Plasminogen Activator/metabolism , Adult , Aged , Aged, 80 and over , Breast Neoplasms/pathology , Endothelial Growth Factors/metabolism , Enzyme-Linked Immunosorbent Assay , Female , Fibroblast Growth Factor 2/metabolism , Humans , Immunosorbent Techniques , Luminescent Measurements , Lymph Nodes/pathology , Lymphokines/metabolism , Middle Aged , Proteins/metabolism , Receptors, Estrogen/metabolism , Receptors, Progesterone/metabolism , Reproducibility of Results , Retrospective Studies , Risk Factors , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factors
3.
J Magn Reson B ; 111(2): 174-7, 1996 May.
Article in English | MEDLINE | ID: mdl-8661276
4.
MAGMA ; 3(1): 49-55, 1995 Mar.
Article in English | MEDLINE | ID: mdl-7600176

ABSTRACT

By extending the formalism previously developed for the design of unshielded, biplanar gradient coils, shielded biplanar B0 coils optimized for homogeneity and either minimum energy or minimum power may be designed. We present results from an integrated approach to shielded biplanar coil design, the results of which are also applicable to gradient coils, enabling the design of shielded coils with a concomitant decrease in total inductance of the coil. Length constraints are also included in the integrated minimization procedure. Results from a preliminary design indicate that high-homogeneity, low-impedance, well-shielded coils result from this design approach.


Subject(s)
Equipment Design , Magnetic Resonance Spectroscopy/instrumentation , Models, Theoretical , Electronics , Fourier Analysis
5.
Z Geburtshilfe Perinatol ; 184(6): 395-400, 1980 Dec.
Article in German | MEDLINE | ID: mdl-7222869

ABSTRACT

The article reports on a controlled, randomized double-blind study by which the effect of intracervically applied Prostaglandin in F2 alpha Gel was examined with regard to the cervix during immature vaginal situation. 124 patients were included in the study. 4 of these had to be dropped because of documentation errors. Age, duration of pregnancy and percentage share of primiparae were approximately equal in both groups. The results show that administration of Prostaglandin Gel via the intracervical route can provoke birth within the next 36 hours in more than 75% of the cases. Only 12.8% of the cases belonged to this category in the control group. Results are somewhat poorer in primiparae. Coarser side effects did not occur in our group, and there is also no higher incidence of surgical deliveries. No negative influence on newborn is to be expected. Results are presented, discussed and compared with those communicated in the available literature.


Subject(s)
Cervix Uteri/drug effects , Labor, Induced/methods , Prostaglandins F, Synthetic/administration & dosage , Adult , Female , Gestational Age , Humans , Pregnancy , Uterine Contraction/drug effects
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