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51.
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J J Langberg J O Franklin J S Landzberg J M Herre L Kee M C Chin S Bharati M Lev R B Himelman N B Schiller 《Journal of the American College of Cardiology》1988,12(1):218-223
The ability to locate catheter position in the left ventricle with respect to endocardial landmarks might enhance the accuracy of ventricular tachycardia mapping. An echo-transponder system (Telectronics, Inc.) was compared with biplane fluoroscopy for left ventricular endocardial mapping. A 6F electrode catheter was modified with the addition of a piezoelectric crystal 5 mm from the tip. This crystal was connected to a transponder that received and transmitted ultrasound, resulting in a discrete artifact on the two-dimensional echocardiographic image corresponding to the position of the catheter tip. Catheters were introduced percutaneously into the left ventricle of nine anesthetized dogs. Two-dimensional echo-transponder and biplane fluoroscopic images were recorded on videotape with the catheter at multiple endocardial sites. Catheter location was marked by delivering radiofrequency current to the distal electrode, creating a small endocardial lesion. Catheter location by echo-transponder and by fluoroscopy were compared with lesion location without knowledge of other data. Location by echo-transponder was 8.7 +/- 5.1 mm from the center of the radiofrequency lesion versus 14 + 7.8 mm by fluoroscopy (n = 15, p = 0.023). Echo-transponder localization is more precise than is biplane fluoroscopy and may enhance the accuracy of left ventricular electrophysiologic mapping. 相似文献
53.
Background Division of retroperitoneal liposarcoma (RPLS) into well-differentiated (WD) and dedifferentiated (DD) subtypes is established;
however, WD and DD are usually treated similarly. We hypothesized that WD and DD have distinct biological behaviors mandating
different treatments.
Methods A prospective sarcoma database identified all primary/recurrent RPLS treated between 1996 and 2007: 77 DD (52%) and 58 WD
(39.2%) patients were analyzed for recurrence rate, recurrence free survival (RFS), and overall survival (OS).
Results At presentation, WD were mostly primary whereas DD were mostly recurrent (75.9% versus 58.4%; p = 0.04). A significant proportion of DD (37.7%) received chemotherapy compared to WD (1.7%; p < 0.0001). Multivisceral resection was more common in DD versus WD (45.5% versus 31%; p = 0.01). Gross total resection rates were equivalent (WD: 86.2%; DD: 85.7%). Overall and local recurrence were higher in
DD versus WD (82.2% versus 50% and 71.2% versus 46.3%; p < 0.0001). Only 3.7% WD recurred as high grade metastatic disease. Median time to recurrence was 55.5 months in WD versus
13.5 months in DD (p < 0.0001). RFS and OS (1, 2, and 5 year) were higher in WD than DD (80.3% versus 55.9%; 65.1% versus 34.1%; 41.9% versus
7.8%; p < 0.0001) and (98% versus 88.1%; 95.6% versus 71.9%; 92.1% versus 36.5%; p < 0.0001) respectively.
Conclusion WD and DD have distinct biological behaviors. Gross total resection is achievable in most WD; unlike DD, high-grade recurrence
is uncommon. Treatment should therefore reflect these biologic differences by maximizing survivorship while avoiding unnecessarily
extensive multivisceral resection.
Synopsis The biological behaviors of well-differentiated and dedifferentiated liposarcomas differ significantly. This article presents
outcomes of two different surgical approaches that were implemented at the UTMDACC, treating these tumors as different disease
entities. 相似文献
54.
Talia Harris Sivaranjan Uppala Naama Lev‐Cohain Yael Adler‐Levy David Shaul Atara Nardi‐Schreiber Gal Sapir Assad Azar Ayelet Gamliel Jacob Sosna J. Moshe Gomori Rachel Katz‐Brull 《NMR in biomedicine》2020,33(2)
Investigation of hyperpolarized substrate metabolism has been showing utility in real‐time determination of in‐cell and in vivo enzymatic activities. Intracellular reaction rates may vary during the course of a measurement, even on the very short time scales of visibility on hyperpolarized MR, due to many factors such as the availability of the substrate and co‐factors in the intracellular space. Despite this potential variation, the kinetic analysis of hyperpolarized signals typically assumes that the same rate constant (and in many cases, the same rate) applies throughout the course of the reaction as observed via the build‐up and decay of the hyperpolarized signals. We demonstrate here an acquisition approach that can null the need for such an assumption and enable the detection of instantaneous changes in the rate of the reaction during an ex vivo hyperpolarized investigation, (i.e. in the course of the decay of one hyperpolarized substrate dose administered to a viable tissue sample ex vivo). This approach utilizes hyperpolarized product selective saturating‐excitation pulses. Similar pulses have been previously utilized in vivo for spectroscopic imaging. However, we show here favorable consequences to kinetic rate determinations in the preparations used. We implement this acquisition strategy for studies on perfused tissue slices and develop a theory that explains why this particular approach enables the determination of changes in enzymatic rates that are monitored via the chemical conversions of hyperpolarized substrates. Real‐time changes in intracellular reaction rates are demonstrated in perfused brain, liver, and xenograft breast cancer tissue slices and provide another potential differentiation parameter for tissue characterization. 相似文献
55.
Adler Y Dagan A Golovchiner G Iakobishvili Z Matz I Lev E Siegel RJ Birnbaum Y 《Ultrasound in medicine & biology》2003,29(3):483-486
We investigated the synergistic effect between low-frequency ultrasound (US) and hydroxyethyl starch (HAES) on blood clot disruption, using different HAES concentrations, US duration and intensity. Human blood clots, 200 to 400 mg in weight, were placed in tubes containing 10 mL of normal saline alone or with HAES 0.1%, 1% or 2%. Clots were randomized to four intensities of US exposure: none, low, medium and high (maximal amplitude of motion at the tip of the horn: 0, 96, 144 and 192 micro m, respectively), and for three durations of US exposure (10, 20 and 40 s). After treatment, the clots were reweighed, and the percent differences in weights were calculated. US intensity, US duration and HAES concentration had a significant effect on the blood clot dissolution (p < 0.001 for all three variables). HAES augmented clot dissolution only when US intensity was medium or high. With low intensity, HAES did not augment clot lysis. CONCLUSIONS: microparticle-containing solutions, such as HAES, have a potential for augmenting clot disruption by US. This effect is highly dependent on US intensity. 相似文献
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The results of a survey of present-day traditional medicinal materials conducted in 1998-1999 in the Kingdom of Jordan are reported. The study covered selected markets of medicinal substances of ethnic communities throughout the kingdom, and also included questioning of the sellers about the healing characteristics of the various materials. The survey yielded information on many and varied medicinal substances, of which 304 are identified according to the following classifications: 236 species of plants (77.6%); 30 species of animals (9.8%); 29 kinds of inorganic substances (9.6%); and 9 materials of other or mixed origin (3%). Analysis of the data showed that some substances were of local origin (41.8%), but the majority of the substances (45.4%) were imported from other countries. 12.8% of the substances were both local and imported. These data demonstrate that there is still a flourishing and well-developed trade in these materials--a trade that is the remnant of a rich and ancient medical culture, which is disappearing from the modern world. 相似文献
60.