48 research outputs found
高齢者(70歳以上)弁膜症に対する外科治療成績と遠隔成績について : 70歳以上と60-69歳における臨床成績と血行動態の検討
Results of open heart surgery in 22 consecutive elderly patients aged 70-76 are presented and compared with results of that procedure in 135 younger patients aged 60-69. The elderly patients presented with valvular disease between August 1, 1987, and September 30, 1994. They consisted of 12 men and 10 women with a mean age of 72.3 years. Fifteen of 22 patients had isolated aortic valve replacement (AVR) or mitral valve replacement (MVR) or repair and 7 patients had combined two or three surgical procedures; 14 of them underwent AVR, 8 underwent MVR or repair, 3 had both mitral and tricuspid valve repair and 2 had coronary artery bypass graft. Preoperatively 54.5% of the patients were in NYHA functional class III and 27.3% were in class IV. Mechanical and biological valves were replaced in 10 and 12 patients, respectively. Preoperative organ dysfunctions in the present patients were associated with the heart in 32%, the lung in 18%, the liver and kidney in 9% and the gastro-intestinal tract in 18%. The only significant correlation between pre and postoperative organ dysfunction was noted in the lung. The younger group averaged 64.2 years old at the time of surgery. Preoperative hemodynamic data in the aortic and mitral valve position indicated lower pressure and LV function in the elderly group than in the younger group, but there were no significant differences between the groups before and after surgery except for in the mean values of m-PCWP in AVR and m-PAP in MVR, which were also significantly improved in the younger group after surgery. The operative mortality rates were 9.1% for elderly patients and 3.0% for the younger patients. Late follow-up of 20 survivors was 86.4±2.9% in the elderly and 82.7±3.9% in the younger patients. There were one late death (1.5%) in the elderly and 10 late deaths (7.4%) in the younger groups. The incidences of freedom from valve-related morbidity were 1.2%/pt-y with 94.7±2.9% being event free in the elderly group and 1.9%/pt-y with 92.4±4.1% being event free in the younger group; these showed no significant differences. These early and long-term results indicate that valve surgery in the elderly has acceptably low mortality and morbidity, and overall survival rate and improvements in symptoms and functional class are comparable to those of younger patients
WIDGET: System Performance and GRB Prompt Optical Observations
The WIDeField telescope for Gamma-ray burst Early Timing (WIDGET) is used for
a fully automated, ultra-wide-field survey aimed at detecting the prompt
optical emission associated with Gamma-ray Bursts (GRBs). WIDGET surveys the
HETE-2 and Swift/BAT pointing directions covering a total field of view of 62
degree x 62 degree every 10 secounds using an unfiltered system. This
monitoring survey allows exploration of the optical emission before the
gamma-ray trigger. The unfiltered magnitude is well converted to the SDSS r'
system at a 0.1 mag level. Since 2004, WIDGET has made a total of ten
simultaneous and one pre-trigger GRB observations. The efficiency of
synchronized observation with HETE-2 is four times better than that of Swift.
There has been no bright optical emission similar to that from GRB 080319B. The
statistical analysis implies that GRB080319B is a rare event. This paper
summarizes the design and operation of the WIDGET system and the simultaneous
GRB observations obtained with this instrument.Comment: 19 pages, 11 figures, Accepted to appear in PAS
A Bezoar Composed of Bilirubin Calcium, Calcium Carbonate, and Fatty Acid Calcium
A 68-year-old Japanese man was diagnosed with bezoar in the stomach, which was endoscopically retrieved. The bezoar was composed of bilirubin calcium, calcium carbonate, and fatty acid calcium. Due to the presence of bilirubin calcium in the bezoar, we performed imaging studies of the bile duct; gallstones and common bile duct stones were identified. Although bezoar with components similar to bile is infrequently encountered, our findings suggest that a bezoar originating from bile should be considered among the differential diagnoses in patients without a recent consumption history of persimmons who demonstrate a mass in the digestive tract. This case highlights the importance of component analysis of gastric bezoars because its findings may alter the treatment plan
Spectral Properties of Prompt Emission of Four Short Gamma-Ray Bursts Observed by the Suzaku-WAM and the Konus-Wind
We have performed a joint analysis of prompt emission from four bright short
gamma-ray bursts (GRBs) with the Suzaku-WAM and the Konus-Wind experiments.
This joint analysis allows us to investigate the spectral properties of
short-duration bursts over a wider energy band with a higher accuracy. We find
that these bursts have a high E, around 1 MeV and have a harder
power-law component than that of long GRBs. However, we can not determine
whether these spectra follow the cut-off power-law model or the Band model. We
also investigated the spectral lag, hardness ratio, inferred isotropic
radiation energy and existence of a soft emission hump, in order to classify
them into short or long GRBs using several criteria, in addition to the burst
duration. We find that all criteria, except for the existence of the soft hump,
support the fact that our four GRB samples are correctly classified as
belonging to the short class. In addition, our broad-band analysis revealed
that there is no evidence of GRBs with a very large hardness ratio, as seen in
the BATSE short GRB sample, and that the spectral lag of our four short GRBs is
consistent with zero, even in the MeV energy band, unlike long GRBs. Although
our short GRB samples are still limited, these results suggest that the
spectral hardness of short GRBs might not differ significantly from that of
long GRBs, and also that the spectral lag at high energies could be a strong
criterion for burst classification.Comment: 23 pages, 6 figures, accepted for Publications of the Astronomical
Society of Japa
A multi band study of the optically dark GRB 051028
Observations were made of the optical afterglow of GRB 051028 with the Lulin
observatory's 1.0 m telescope and the WIDGET robotic telescope system. R band
photometric data points were obtained on 2005 October 28 (UT), or 0.095-0.180
days after the burst. There is a possible plateau in the optical light curve
around 0.1 days after the burst; the light curve resembles optically bright
afterglows (e.g. GRB 041006, GRB 050319, GRB060605) in shape of the light curve
but not in brightness. The brightness of the GRB 051028 afterglow is 3
magnitudes fainter than that of one of the dark events, GRB 020124. Optically
dark GRBs have been attributed to dust extinction within the host galaxy or
high redshift. However, the spectrum analysis of the X-rays implies that there
is no significant absorption by the host galaxy. Furthermore, according to the
model theoretical calculation of the Ly absorption to find the limit of
GRB 051028's redshift, the expected band absorption is not high enough to
explain the darkness of the afterglow. While the present results disfavor
either the high-redshift hypothesis or the high extinction scenario for
optically dark bursts, they are consistent with the possibility that the
brightness of the optical afterglow, intrinsically dark.Comment: 5page, 5 figures, 1 table, accepted for publication in PASJ Letter.
PASJ styl
Can sufficient preoperative information of intracranial aneurysms be obtained by using 320-row detector CT angiography alone?
Abstract Purpose To determine whether sufficient pre-surgical treatment information of unruptured intracranial aneurysms can be obtained by using 320-row detector CT angiography (CTA) alone. Materials and methods We enrolled 40 consecutive patients with unruptured intracranial aneurysms. All patients were prospectively conducted to perform 320-detector CTA as the only preoperative modality. Two blinded readers independently assessed CTA images. Interobserver agreement and the agreement between CTA and surgical findings were determined by calculating the j coefficient. The referring neurosurgeons judged the usefulness of the information provided by CTA for treatment decisions. Results All patients had surgery without intraarterial digital subtraction angiography. Agreement between CTA and surgical findings was excellent for the aneurysm location (j = 1.0) and good for the shape (j = 0.71), neck (j = 0.74) and its relationship with adjacent branches (j = 0.71). Information obtained with 320-detector CTA was highly useful for surgical treatment in 37 of 40 (93 %) patients, although small perforators deriving from the aneurysm in 2 cases were not fully visualized on CTA images. Conclusion In most patients with unruptured intracranial aneurysms, sufficient pre-surgical treatment information can be obtained by using 320-detector CTA alone
Spectral evolution of GRB 060904A observed with Swift and Suzaku -- Possibility of Inefficient Electron Acceleration
We observed an X-ray afterglow of GRB 060904A with the Swift and Suzaku
satellites. We found rapid spectral softening during both the prompt tail phase
and the decline phase of an X-ray flare in the BAT and XRT data. The observed
spectra were fit by power-law photon indices which rapidly changed from to within a few hundred
seconds in the prompt tail. This is one of the steepest X-ray spectra ever
observed, making it quite difficult to explain by simple electron acceleration
and synchrotron radiation. Then, we applied an alternative spectral fitting
using a broken power-law with exponential cutoff (BPEC) model. It is valid to
consider the situation that the cutoff energy is equivalent to the synchrotron
frequency of the maximum energy electrons in their energy distribution. Since
the spectral cutoff appears in the soft X-ray band, we conclude the electron
acceleration has been inefficient in the internal shocks of GRB 060904A. These
cutoff spectra suddenly disappeared at the transition time from the prompt tail
phase to the shallow decay one. After that, typical afterglow spectra with the
photon indices of 2.0 are continuously and preciously monitored by both XRT and
Suzaku/XIS up to 1 day since the burst trigger time. We could successfully
trace the temporal history of two characteristic break energies (peak energy
and cutoff energy) and they show the time dependence of while the following afterglow spectra are quite stable. This fact
indicates that the emitting material of prompt tail is due to completely
different dynamics from the shallow decay component. Therefore we conclude the
emission sites of two distinct phenomena obviously differ from each other.Comment: 19 pages, 9 figures, accepted for publication in PASJ (Suzaku 2nd
Special Issue