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We adopted laser Thomson scattering for measuring the electron density and the electron temperature of microwave plasmas produced in helium at the pressures higher than the atmospheric pressure. The electron density decreased while we observed the increase in the electron temperature with the pressure. These are reasonable results by considering the decrease in the reduced electric field, the dominant loss of electrons via three-body recombination with helium as the third body, and the production of electrons with medium energy via heavy particle collisions at the high gas pressure. The temporal variation of the electron temperature had the rise and the fall time constants of approximately 10 ns. The rapid heating and cooling of the electron temperature are due to the fast energy transfer from electrons to helium because of the high collision frequency in the high-pressure discharge.

Between April 1989 and October 1993, 35 patients underwent aortic arch reconstruction for aneurysms using cardiopulmonary bypass (CPB) with selective cerebral perfusion (SCP). Of the 35 patients, the initial 19 (Group P) consecutively received simplified SCP (partial brachiocephalic perfusion; PBP), and the next 16 (Group S) were consecutively treated with standard SCP. For cerebral protection, blood was supplied to the right axillary artery in Group P, and to the right axillary and the left common carotid arteries in Group S. The aneurysms was aortic dissection in 24 patients, and was secondary to arteriosclerosis in the remaining 11. Partial replacement of the aortic arch together with the ascending aorta was the most commonly performed procedure in both groups. The cardiopulmonary bypass time and the cardiac arrest time were not significantly different between the two groups. The overall cerebral perfusion time was significantly longer in Group S (100 min) than in Group P (65 min); however, when 2 patients with an accidental prolongation of the cerebral perfusion time in Group S were excluded, there was no significant difference in the cerebral perfusion time between the two groups. Early death occurred in 3 patients (15.8%) in Group P, and 2 patients (12.5%) in Group S, however, there were no deaths related to the selective cerebral perfusion technique, and there were no late deaths in either group. Cerebral complications were seen in 1 patient in each group (6.3% vs. 6.7%, not significant). These results suggest that the simplified SCP (PBP) under hypothermic CPB provides as satisfactory cerebral protection as standard SCP, so long as the patency of the circle of Willis is confirmed.(ABSTRACT TRUNCATED AT 250 WORDS)

We studied electrophysiological, oxygen metabolic, and histological variables in dogs to establish the reliability and safety of partial brachiocephalic perfusion (PBP) under hypothermic cardiopulmonary bypass (CPB) at 23 degrees-25 degrees C. Sixteen mongrel dogs were divided into two groups. Six (control group) underwent typical hypothermic CPB for 90 min, and 10 (PBP group) underwent PBP under hypothermic CPB for 90 min. During core cooling on the CPB, a progressive reduction in voltage and slowing of frequency of the electroencephalogram (EEG) was observed. At around 23 degrees C nasopharyngeal temperature the tracing became almost flat and remained so throughout the hypothermic CPB or the PBP under hypothermic CPB. Consistent recovery of the EEG was, however, observed during the period of rewarming on the CPB, and the voltage and frequency of the EEG recovered to control levels on weaning off CPB at 36 degrees C in both groups. In the PBP group, the cerebral arteriovenous oxygen (AVO2) difference was 12.4 +/- 4.0 vol% before beginning the CPB, and it was 5.6 +/- 2.7, 5.7 +/- 3.1, 5.4 +/- 3.3, and 4.9 +/- 2.9 vol% at 10, 30, 60, and 90 min respectively after commencement of the PBP under hypothermic CPB. The cerebral AVO2 difference measured 10 min after commencement of the PBP was significantly less than that in the control group (P less than 0.05), but otherwise there were no significant differences between cerebral AVO2 differences in the two groups. Concentration of serum creatine kinase-BB (CK-BB) gradually increased in proportion to the duration of CPB in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

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Feline immunodeficiency virus (FIV) induces a disease similar to acquired immunodeficiency syndrome (AIDS) in cats, yet in contrast to human immunodeficiency virus (HIV), CD4 is not the viral receptor. We identified a primary receptor for FIV as CD134 (OX40), a T cell activation antigen and costimulatory molecule. CD134 expression promotes viral binding and renders cells permissive for viral entry, productive infection, and syncytium formation. Infection is CXCR4-dependent, analogous to infection with X4 strains of HIV. Thus, despite the evolutionary divergence of the feline and human lentiviruses, both viruses use receptors that target the virus to a subset of cells that are pivotal to the acquired immune response.

A 58-year-old Japanese woman who had a history of aortic valve replacement for congenital bicuspid valve, was admitted for investigation of facial edema and of pulselessness of the right leg. Physical examination disclosed the patient suffering from a superior vena cava syndrome. On auscultation, a continuous murmur was heard at the left lower sternal border. Computed tomographic scans revealed aortic dissection extending from the ascending aorta to the bifurcation. Echocardiography showed an intimal flap in the dilated ascending aorta, but not abnormal blood flow from the aorta to the right atrium was detected. Cardiac catheterization and aortography, however, allowed a correct diagnosis of aortic dissection with fistula to the right atrium and with obstruction of the right common iliac artery. The patient received emergency aortic root replacement and reconstruction of the coronary arteries and then recovered uneventfully.

A 57-year-old Japanese man presented with symptoms of congestive heart failure 9 years after aortic valve replacement. On auscultation, a continuous murmur was heard at the left lower sternal border. Chest radiograph showed moderate cardiomegaly and a widened upper mediastinum. Computed tomographic scans showed a dilated ascending aorta, in which there was no intimal flap, and also showed a large mass which compressed the right atrium. Two-dimensional Doppler echocardiography revealed abnormal continuous blood flow directed from the dilated ascending aorta to the right atrium and no periprosthetic leak. At operation, a false aneurysm of the ascending aorta which originated from the aortotomy suture line and a fistula from the aorta to the right atrium were confirmed. The fistula was closed with pledgeted sutures, and the ascending aorta was replaced with a collagen-coated double woven velour dacron graft. The patient recovered uneventfully. Computed tomographic scan and two-dimensional echocardiography are complementary techniques for reliable non-invasive assessment of the complexity of an aortic aneurysm.

A case of spontaneous non-traumatic rupture of the thoracic aorta in a hypertensive patient is presented. The clinical findings suggested acute aortic dissection, and a large pericardial effusion was detected by echocardiography. The typical angiographic features of aortic dissection were not found. Autopsy revealed a longitudinal intimal tear and a rupture in the postero-lateral aspect of the ascending aorta. No false lumen was seen in the ascending aorta. When acute intrapericardial or intrapleural bleeding develops with no evidence of aortic aneurysm or dissection, spontaneous aortic rupture should be suspected.

A 74-year-old woman presented with severe dyspnea without dysphagia. Computed tomographic scans and Digital subtraction angiography revealed the left aortic arch with an aberrant right subclavian artery arising from the Kommerell's diverticulum and tracheal compression. The aortic arch and the Kommerell's diverticulum were aneurysmal and were responsible for this compression. Surgical relief was accomplished by replacement of the aortic arch and reconstruction of the four brachiocephalic vessels with vascular prostheses through a median sternotomy incision extending into the right supraclavicular region.