In a clinical trial we studied left ventricular performance at rest in 50 patients with unstable angina by radionuclide techniques. Thallium-201 scintigraphy was performed on admission in 38 patients ...and repeated after 48 hr in 32 patients. Also dynamic blood pool scintigraphy was performed in 37 patients on admission and in 45 patients after 48 hr. Of the 50 patients, 27 (54%) had no recurrent episodes of myocardial ischemia, but 23 (46%) patients showed recurrent ischemic episodes of whom 11 (22%) patients developed a myocardial infarction. The thallium-201 images showed perfusion defects in 27 (71%) of the 38 patients studied on admission and in 20 (63%) of the 32 patients studied at 48 hr. No relation between clinical outcome and presence or absence of defects was observed. Left ventricular ejection fraction was abnormal (less than 50%) in 19 (51%) of the 37 patients on admission and in 29 (64%) of the 45 patients studied at 48 hr. As with thallium-201, no relation could be established between clinical outcome and left ventricular ejection fraction. It is concluded that radionuclide techniques are useful to provide insight into the pathophysiological mechanism of unstable angina, but they are not helpful for the short-time assessment of clinical outcome.
Novel developments in intravascular imaging van der Steen, A.F.W.; Cespedes, E.I.; de Korte, C.L. ...
1998 IEEE Ultrasonics Symposium. Proceedings (Cat. No. 98CH36102),
1998, Volume:
2
Conference Proceeding
In the development of intravascular ultrasound (IVUS), a serious emphasis has been given to the improvement of the image quality in terms of resolution. The image quality is indeed a very important ...issue, but there is lot more information hidden in the ultrasound signals than is currently exploited by commercially available IVUS equipment. Over the past few years, at the Thorax centre we have been exploring the possibilities of analysing sequences of radiofrequency (RF) traces. This could provide a significant extension of the functionality of the IVUS machines. It gives possibilities for local elasticity assessment, flow estimation and enhanced lumen detection. This paper is an up to date impression of where RF-data analysis has taken us.
The effect of proteolysis on the transcriptional properties of reconstituted rat liver chromatin was studied. Within the sensitivity of currently available methods, proteolysis of chromosomal ...proteins by chromatin-bound protease during chromatin reconstitution has no apparent effect on: (1) number of initiation sites, (2) proportion of reiterating and unique sequences of DNA transcribed, (3) size of the RNA transcribed, and (4) transcription of DNA sequences complementary to poly(A) containing messenger RNA.
New IVUS-based blood velocity profile measurements are under development For these velocity measurements catheter placement in an artery is necessary, but induces disturbances in the native velocity ...profiles. To what degree the velocity profiles are disturbed by the catheter is studied by computational fluid dynamics. Therefore a straight tube having a catheter inside, is studied for 4 inflow velocities (0.05, 0.1, 0.2, 0.4 m/s) and two catheter positions (in the center and out of the center of the tube). The influence of the catheter size on the velocity profiles is studied as well. Central catheter placement reduced the peak to mean velocity ratio, compared to no catheter inside the tube, by 24%. In contrast, catheter placement out of the center of the tube increased the peak to mean velocity ratio by 14%. These values are independent of the inflow velocities and minimally dependent on changes in catheter size. The shear stress values, however, are dependent on both catheter location and catheter size.
In 1983 we published the results of 12 months of behaviour assessment in an old people's home. We noticed an increase in physical and psychosocial problems. In the following 18 months we observed a ...further increase, both in the cross-sectional group as well as in the longitudinal group. Newly admitted people have rather serious problems from the onset. Furthermore, there is a marked increase from then on. The most vulnerable category consists of those elderly who die or are relocated to a nursing home within a short period of time. In the past the temporary increase in care for this group was compensated by the admittance of relatively healthy and young people. This equilibrium is now disturbed by the more advanced age and greater dependency of newly admitted elderly. In our research we find minor differences in psychosocial aspects between people dying and those relocated to a nursing home. The question remains, whether people in their last period of life should be relocated to a nursing home. We think the old people's home has an important task here. Because the lack of social contact plays an important role in the development of other problems, we plead for interventions in this area. We mentioned two possible modes of intervention. Our first impression is rather positive.
Endovascular treatment of cerebral aneurysms with detachable coils has proven to be a save and effective treatment. But long-term recurrence due to aneurysm regrowth or coil compaction has been ...reported in up to thirty percent of cases. Therefore a growing number of previously coiled aneurysms have to be retreated by coiling or, in some circumstances, by clipping. We present a consecutive series of ten patients who underwent surgical clipping for recurrent aneurysms after primary coil embolization.
During a 4-year period ten patients with intracranial aneurysms previously treated by coil embolization underwent surgery for clipping of recanalized aneurysms. All aneurysms were located in the anterior circulation (internal carotid artery ICA, 2; middle cerebral artery MCA, 3; anterior communicating artery AcomA, 5). Clinical data and imaging studies of the patients were analyzed retrospectively.
All recurrences were detected by routine control angiograms within a median period of 14 months after primary treatment. In three aneurysms treated for SAH dense arachnoid scarring around the aneurysm sac was noted. In four cases, coils were found intraoperatively to be extruding through the aneurysm sac into the subarachnoid space. Each aneurysm could be clipped without affecting the perfusion of the parent vessel. In one patient the aneurysm sac including the coil package was resected. In one patient one of the central anteromedial arteries was injured during dissection due to dense arachnoid scarring because of prior SAH. As a consequence infarction of the head of the caudate nucleus without neurological compromise was observed on follow-up CT scans. Another patient developed transient aphasia due to vasospasm in the early postoperative period with complete restitution. In the end all patients had an uneventful recovery. Removal of the coil package was not necessary in most cases. Clipping of the aneurysm neck was possible even in cases with coil dislocation into the parent vessel.
Clipping of previously coiled aneurysms is a unique problem for vascular neurosurgeons. In most cases clipping is feasible. Clipping should still be considered as a definite treatment option in previously coiled recurrent aneurysms. Results in this small series were good.
Phys.Atom.Nucl. 65 (2002) 1778-1784; Yad.Fiz. 65 (2002) 1826-1832 A search for the muon catalyzed fusion reaction dd --> ^4He +\gamma in the
dd\mu muonic molecule was performed using the experimental ...\mu CF installation
TRITON and NaI(Tl) detectors for \gamma-quanta. The high pressure target filled
with deuterium at temperatures from 85 K to 800 K was exposed to the negative
muon beam of the JINR phasotron to detect \gamma-quanta with energy 23.8 MeV.
The first experimental estimation for the yield of the radiative deuteron
capture from the dd\mu state J=1 was obtained at the level n_{\gamma}\leq
2\times 10^{-5} per one fusion.
A search for the muon catalyzed fusion reaction dd --> ^4He +\gamma in the dd\mu muonic molecule was performed using the experimental \mu CF installation TRITON and NaI(Tl) detectors for ...\gamma-quanta. The high pressure target filled with deuterium at temperatures from 85 K to 800 K was exposed to the negative muon beam of the JINR phasotron to detect \gamma-quanta with energy 23.8 MeV. The first experimental estimation for the yield of the radiative deuteron capture from the dd\mu state J=1 was obtained at the level n_{\gamma}\leq 2\times 10^{-5} per one fusion.
