Silane catecholates: versatile tools for self-assembled dynamic covalent bond chemistry.

Shape-persistent macrocycles and 3D nanocages have been prepared in one-pot under MeCN-promoted dynamic covalent bond conditions starting from silane catecholates, whose structures were confirmed by X-ray crystallography. Cation-exchange reactions of macrocycles and nanocages were performed along with the encapsulation of ammonium ions within the cavity of an anionic macrocycle and a tetrahedral nanocage.

"Megatrends" driving healthcare facility design: a look at the major trends that will shape medical facility design.

Changes in medical construction and design are accelerating exponentially, and anyone who can anticipate where these changes are going to happen will be at an advantage. Knowing the "Megatrends" defining and driving the future of healthcare delivery and healthcare facility design will help decision makers anticipate the future.

Three-dimensional finite element analysis of stress distribution in composite resin cores with fiber posts of varying diameters.

Using three-dimensional finite element analysis (3D-FEA), stress distributions in the remaining radicular tooth structure were investigated under the condition of varying diameters of fiber post for fiber post-reinforced composite resin cores (fiber post and core) in maxillary central incisors. Four 3D-FEA models were constructed: (1) fiber post (ø1.2, ø1.4, and ø1.6 mm) and composite resin core; and (2) gold-cast post and core. Maximum stresses in the tooth structure for fiber post and core were higher than that for gold-cast post and core. In the former models, stresses in the tooth structure as well as in the composite resin were slightly reduced with increase in fiber post diameter. These results thus suggested that to reduce stress in the remaining radicular tooth with a large coronal defect, it is recommended to accompany a composite resin core with a fiber post of a large diameter.

Hemoperfusion with an immobilized polymyxin B fiber column reduces circulating interleukin-8 concentrations.

In the present study, we examined whether the performance of hemoperfusion with an immobilized polymyxin B fiber column (DHP-PMX) reduces circulating interleukin-8 concentration in patients with sepsis. Fifteen patients with sepsis satisfying the following criteria were enrolled in the study: (i) signs of systemic inflammatory response syndrome caused by infection; and (ii) mean arterial blood pressure > or =60 mm Hg (irrespective of the use of catecholamines). A thermodilution catheter was inserted prior to DHP-PMX for appropriate intravenous infusion, and the DHP-PMX was carried out twice at 24 h intervals (for 3 h each time). Circulating interleukin-8 concentration was measured seven times. The sequential organ failure assessment (SOFA) score was calculated twice. Circulating interleukin-8 concentration was 55 +/- 15.7 pg/mL before DHP-PMX, while it was 101 +/- 58.8 pg/mL immediately after the first session of treatment. It was 24 +/- 9.0 pg/mL before the second session of DHP-PMX, and it was 28 +/- 8.0 pg/mL immediately after the second session. The IL-8 level was 17 +/- 4.3 pg/mL at 48 h afterward, and 18 +/- 4.3 pg/mL at 72 h afterward, showing a significant decrease from 48 h onwards, compared with before treatment (P < 0.05). The SOFA score was 9 +/- 1.5 and the APACHE II score was 19 +/- 2.0 before DHP-PMX, while the SOFA score was 7.0 +/- 0.9 at 72 h afterward, showing a significant decrease compared with before treatment (P < 0.05). The present findings indicate that DHP-PMX indirectly reduces circulating interleukin-8 concentration and improves SOFA score.

Hemoperfusion with an immobilized polymyxin B fiber column improves tissue oxygen metabolism.

Recently, direct hemoperfusion with a polymyxin B-coated fiber column (DHP-PMX) has been increasingly used for the treatment of sepsis, and an improvement in outcomes has been reported. However, the mechanism of the method is not known in detail. In the present study, we examined whether the performance of DHP-PMX improved tissue oxygen metabolism in patients with sepsis. Twenty-two patients with sepsis, satisfying the following criteria, were enrolled in the study: (i) signs of systemic inflammatory response syndrome caused by infection; and (ii) mean arterial blood pressure > or =60 mm Hg (irrespective of the use of catecholamines). A thermodilution catheter was inserted prior to DHP-PMX for appropriate intravenous infusion, and the DHP-PMX was carried out twice within 24 h (for 3 h each time). Then, the gastric mucosal-arterial PCO(2) difference (PCO(2) gap) was calculated as the gastric mucosal PCO(2) minus arterial PCO(2). A PCO(2) gap > or =8 mm Hg was used to define abnormal tissue oxygen metabolism. PCO(2) gap was measured before PMX-DHP, as well as 24, 48, and 72 h afterward. PCO(2) gap was 20 +/- 4.9 mm Hg before DHP-PMX vs. 16 +/- 2.7 mm Hg (P = 0.189) at 24 h, 12 +/- 2.8 mm Hg (P = 0.046) at 48 h, and 11 +/- 2.2 mm Hg (P = 0.045) at 72 h afterward, showing a significant decrease from 48 h onward compared with before treatment. These findings suggest that DHP-PMX improves tissue oxygen metabolism.

Hemoperfusion with an immobilized polymyxin B column reduces the blood level of neutrophil elastase.

BACKGROUND: We investigated whether direct hemoperfusion with an immobilized polymyxin B column (DHP with PMX) could reduce the blood level of neutrophil elastase. METHODS: 20 sepsis patients were enrolled in the study. DHP with PMX was performed twice within a 24-hour period. Neutrophil elastase was measured 7 times. RESULTS: Neutrophil elastase was 468 +/- 75.1 microg/l, while it was 1,531 +/- 201.7 microg/l immediately after the first session, declined to 351 +/- 73.9 microg/l before the second session of DHP with PMX, and increased again to 599.3 +/- 112.7 microg/l immediately after the second session, 328 +/- 73.7 microg/l at 24 h, 264 +/- 39.3 microg/l at 48 h, and 230 +/- 36.1 microg/l at 72 h after DHP with PMX. The levels from 48 h onwards were significantly lower compared with that before treatment. CONCLUSION: DHP with PMX has an overall effect that reduces circulating neutrophil elastase levels.

Cholesterol embolization treated with corticosteroids--two case reports.

Cholesterol embolization (CE) is a potentially serious complication associated with invasive arterial maneuvers, in which standard therapy has not been established. We experienced two cases of CE in patients with severe atherosclerosis whose renal function deteriorated within a few months after invasive arterial maneuvers. CE was confirmed either by renal biopsy (case 1) or skin biopsy (case 2). Oral administration of prednisolone at a daily dose of 30 mg (0.4 mg/kg) was effective to improve their renal function. Our observation suggests that corticosteroid therapy may be beneficial in some patients with CE.

Hemoperfusion with an immobilized polymyxin B fiber column inhibits activation of vascular endothelial cells.

Involvement of the activation of neutrophils and vascular endothelial cells in the pathology of sepsis has recently been reported. We therefore investigated whether direct hemoperfusion (DHP) with a polymyxin B immobilized fiber column (PMX) could reduce the level of plasminogen activator inhibitor-1 (PAI-1), an index of vascular endothelial cell activation. Twelve sepsis patients satisfying the following criteria were enrolled in the study: (i) stable global oxygen metabolism (oxygen delivery index>500 mL/min/m2 and oxygen consumption index>120 mL/min/m2); (ii) abnormal tissue oxygen metabolism (PCO2 gap: gastric mucosal PCO2 minus arterial PCO2 difference>8 mm Hg); and (iii) mean blood pressure>or=60 mm Hg. Direct hemoperfusion with PMX was performed twice (for 3 h each time) within 24 h. Plasminogen activator inhibitor-1 was measured a total of 5 times: before PMX-DHP, immediately after the first DHP with PMX session (3 h after the start), and 24, 48, and 72 h afterward. The PAI-1 value was 150+/-30.0 ng/mL before DHP with PMX, 178+/-60.0 ng/mL immediately after DHP with PMX, 90+/-22.1 ng/mL at 24 h after, 65+/-21.0 ng/mL at 48 h after, and 64+/-18.3 ng/mL 72 h after. The values were significantly lower from 48 h onward compared with baseline. These data suggest that DHP with PMX inhibits vascular endothelial cell activation.

Verapamil prevents impairment in filterability of human erythrocytes exposed to oxidative stress.

Effects of oxidative stress on intact human erythrocytes were investigated using tert-butyl hydroperoxide (tBHP). Exposure of erythrocytes to tBHP caused a marked decrease in filterability in a time-dependent manner. Erythrocytes exposed to tBHP also show an increase in mean corpuscular volume and a remarkable formation of methemoglobin (met-Hb) without any appearance of hemichromes that form Heinz bodies. High performance liquid chromatography demonstrated that the tBHP-treated erythrocytes exhibited an apparent decrease in the membrane phospholipid, phosphatidylethanolamine (PE). The decrease in PE was inhibited by pretreatment with ascorbate, but not with verapamil. SDS-polyacrylamide gel electrophoresis of the tBHP-treated erythrocyte membrane showed a degradation of spectrin, band 3, band 4.2, and band 4.5, accompanied by the appearance of low-molecular-weight products. The degradation of the membrane proteins was not prevented by pretreatment with verapamil or ascorbate. However, the pretreatment with verapamil but not with ascorbate revealed significant inhibition of the tBHP-induced impairment in filterability in the presence of extracellular Ca2+. Thus, the present study shows that verapamil, a potent drug in reperfusion therapy, plays an important role in protection against oxidative injury, based on a close linkage among decreased filterability, met-Hb formation, and impaired membrane integrity.

Bezold-Jarisch-like reflex during Brockenbrough's procedure for radiofrequency catheter ablation of focal left atrial fibrillation: report of two cases.

Brockenbrough's puncture technique has been widely conducted in the electrophysiologic laboratory. We report here two cases exhibiting a rare complication of this procedure, which arose during the conduct of catheter ablation using radiofrequency energy delivered to the pulmonary vein for the treatment of focal left atrial fibrillation. These cases exhibited marked sinus bradycardia and profound hypotension, suggestive of a Bezold-Jarisch-like reflex, observed immediately after Brockenbrough's procedure but before radiofrequency application. ST elevation in the inferior leads was also observed in spite of normal coronary angiograms. This unanticipated transient complication was treated by intravenous administration of atropine, which had no influence on the ablation procedure or prognosis. This is speculated to be attributable to the elevation of vagal tone caused by the mechanical effects of transseptal puncture on the interatrial vagal network.

Reentrant atrial tachycardia originating from the superior vena cava.

A 52-years old man with a previous pericardiotomy for idiopathic constrictive pericarditis underwent catheter ablation for drug-resistant atrial tachycardia (AT). The mechanism of the AT was considered as reentry because of resetting response and the entrainment phenomenon during AT. We introduced a 64-electrode basket catheter into the superior vena cava (SVC) during AT to obtain precise mapping. A fractionated potential preceding local atrial electrogram was recorded in the SVC. The earliest activation site of the potential was located at the anterior aspect of the SVC, 2 cm above the SVC-right atrium junction determined fluoroscopically. The fractionated potential at this site preceded the onset of the P wave by 115 msec. Radiofrequency catheter ablation at this site eliminated the tachycardia. At 6 months follow-up, the patient is free of AT. Reentrant AT involving the SVC is a candidate of RF ablation. Multielectrode basket catheter is useful for a detailed mapping of the SVC.

Sick sinus syndrome disclosed by the successful radiofrequency catheter ablation of persistent common atrial flutter.

Sick sinus syndrome was disclosed in a 77 year-old man after a radiofrequency (RF) linear catheter ablation of cavotricuspid isthmus for persistent common atrial flutter. Prolongation of corrected sinus node recovery time, sinoatrial conduction time and AH interval, as observed after RF ablation, suggested binodal (sinus as well as atrioventricular node) dysfunction. Adams-Stokes syndrome due to sinus arrest was encountered on the day of RF ablation and a permanent DDD pacemaker was implanted consequently. Our experience indicates that careful observation is very important after the RF ablation when atrial flutter is associated with sick sinus syndrome. The present case suggests that binodal dysfunction underlies persistent atrial flutter and vice versa.