Gas transfer and in vitro and in vivo blood compatibility of a fluorinated polyimide membrane with an ultrathin skin layer

The authors have synthesized fluorinated polyimides to develop a novel membrane oxygenator combining excellent gas transfer and blood compatibility. Gas exchange membranes of fluorinated polyimides prepared by a dry/wet process showed an asymmetric structure and consisted of an ultrathin and defect-free skin layer supported by a porous substructure. The asymmetric polyimide membranes never incurred plasma leakage because of the defect-free skin layer of the membrane surface. The calculated, apparent defect-free skin layer thickness of the asymmetric membrane was approximately 20 nm. Carbon dioxide and oxygen transfer rates through the membranes were dramatically enhanced because of the ultrathin skin layer and were 96 and 64 times larger than those determined in currently available oxygenator polymer membranes, such as polydimethylsiloxane (PDMS). For the evaluation of in vitro blood compatibility, platelet adhesion and plasma protein adsorption on the polyimide membranes were measured by using scanning electron microscopic examination and an amino acid analyzer. Deformation and aggregation of platelets adherent to the membranes were not observed, and the number of platelets was 1.6 micrograms/cm2, which was one-sixth less than the value measured in PDMS. For in vivo evaluation, the polymer tubes were implanted in the femoral vein of a mongrel dog for 7 days. Thrombus formation and fibrin were found on the surface of PDMS. However, thrombus formation was not observed on the polyimide. These results indicate that the fluorinated polyimides show excellent blood compatibility and are a promising membrane material for an oxygenator.     

Fabrication techniques and characteristics of Al-SiO2laminated optical polarizers

Techniques for fabricating laminated polarizers (LAMIPOLs), which consist of alternating laminated layers of aluminum and silica, for the wavelength region λ>1 μm, are investigated. The oxidation of Al films is prevented by a suitable choice of deposition conditions. The surfaces of SiO₂ films are smoothed by bias sputtering. A 10 μm thick LAMIPOL was obtained having an insertion loss of 0.15 dB and an extinction ratio of greater than 60 dB at the wavelength of 1.3 μm. These characteristics can be estimated from the attenuated constants of the fundamental modes even when higher modes are considered     

Bruton's tyrosine kinase regulates apoptosis and JNK/SAPK kinase activity

Mast cells derived from Bruton's tyrosine kinase (Btk)-defective xid or btk null mice showed greater expansion in culture containing interleukin-3 (IL-3) than those from wild-type (wt) mice. Although the proliferative response to IL-3 was not significantly different between the wt and xid mast cells, xid and btk null mast cells died by apoptosis more slowly than their wt counterparts upon IL-3 deprivation. Consistent with these findings, the apoptosis-linked c-Jun N-terminal kinase/stress-activated protein kinase (JNK) activity was compromised in these btk-mutated cells upon Fc(epsilon)RI crosslinking or upon stimulation with IL-3 or with stem cell factor. p38 activity was less severely, but significantly, affected by btk mutation, whereas extracellular signal-regulated kinases were not affected by the same mutation. Btk-mediated regulation of apoptosis and JNK activity was confirmed by reconstitution of btk null mutant mast cells with the wt btk cDNA. Furthermore, growth factor withdrawal induced the activation and sustained activity of JNK in wt mast cells, while JNK activity was consistently lower in btk-mutated mast cells. These results support the notion that Btk regulates apoptosis through the JNK activation.     

Light beam redistribution using computer-generated phase plates

The use of two phase plates for light-beam power redistribution is proposed. The first plate is designed so that the desired power distribution is obtained by near-field diffraction; the purpose of the second plate is the correction of the phase front. The deviation is based on ray optics, which is a good approximation in practical situations. As an example, design and fabrication of the phase plate for 1:2 branching of single-mode fibers are described. The phase plates have a computer-generated pattern and are fabricated by electron-beam lithography. Experimental verification of beam branching is presented     

Low-threshold current low-voltage vertical-cavity surface-emittinglasers with low-Al-content p-type mirrors grown by MOCVD

InGaAs quantum-well vertical-cavity surface-emitting lasers with low-Al-content p-type mirrors grown by metalorganic chemical vapor deposition (MOCVD) have have been characterized. Series resistance in p-type Al_xGa_1-xAs/GaAs mirrors decreases drastically as the Al content in Al_xGa_1-xAs decreases from AlAs. Air-post devices with a p-type Al_0.06Ga _0.4As/GaAs top mirror exhibit a room temperature CW threshold current of 1.8 mA at an operating voltage of 2.0 V (with a threshold power consumption at 3.6 mW)     

Analysis of cases allowed to cease erythromycin therapy for diffuse panbronchiolitis--comparative study between patients with cessation of the therapy and patients continuing the therapy

We investigated the effect of erythromycin (EM) in patients with diffuse panbronchiolitis (DPB) who were divided into 2 groups, the short term group with 8 patients who were treated for at least 2 years and the long term group with 7 patients who were treated for more than 3 years. Each mean value of %VC, FEV1.0, FEV1.0% and PaO2 two years after administration to these patients was improved than before administration of EM, with the exception of PaO2 in the long term group. There was no change in %VC, FEV1.0, FEV1.0% or PaO2 in each group between one year after the therapy and thereafter, with the exception of the fact that FEV1.0% in the short term group, except patients restarting EM therapy, 2 years after the therapy was significantly higher than in the long term group. One patient was readministered EM because of recurrence of DPB after cessation of EM therapy, whose %VC, FEV1.0 and PaO2, but not FEV1.0%, one year after the therapy were increased in those before the therapy. The Neutrophil proportion in the bronchoalveolar lavage (BAL) fluid in this patient was still high after the therapy (94.5%), while that in the patients with cessation of the therapy was improved to the level of less than 8%. Neutrophil proportion in BAL fluids in the patients with continuation of the therapy revealed a high or low level after the therapy. These results suggest that the patients, whose %VC, FEB1.0% and PaO2 were improved and whose proportion of neutrophils in BAL fluid reduced to a normal level compared with those before EM therapy, can be allowed to cease therapy after 2 years or more of EM therapy.     

Prolonged effect of troglitazone (CS-045) on xenograft survival of hybrid artificial pancreas

Troglitazone (CS-045), a thiazolidinedione derivative, is a new oral antidiabetic agent that enhances insulin sensitivity and improves insulin responsiveness. In this study we examined the effects of CS-045 on the survival of xenografted bioartificial pancreas. Isolated rat islets were microencapsulated with three-layer agarose microcapsules (polybrene, carboxymethyl cellulose, and an agarose-polystyrene sulfonic acid mixture). Diabetes was induced by intraperitoneal injection of streptozotocin 220 mg/kg. Recipient diabetic mice were separated into two groups. In the CS-045 treated group, the recipient mice were given feed mixed with CS-045 (0.2% w/w) starting from 1 wk before transplantation up to graft failure. The mice in the control group had feed without CS-045. Three hundred microencapsulated rat islets were xenotransplanted into the intraperitoneal cavity of each recipient mouse in both groups. One month after xenotransplantation, IVGTT was performed for all recipients. Xenotransplantation of 300 rat islets in microcapsules decreased the nonfasting blood glucose levels of both groups within 2 days. In the CS-045-treated group (n = 3), the normoglycemic period lasted for more than 1 mo without administration of immunosuppressive drugs (45 +/- 4.3 days). However, in the control group (n = 4), the blood glucose levels of all recipients were already elevated on day 4. In the IVGTT study, the glucose assimilation was markedly and significantly better in the CS-045-treated group than in the control group (K = 1.7 +/- 0.1 vs. 0.7 +/- 0.28 respectively, p < 0.01). This study demonstrates that a newly developed oral antidiabetic agent, CS-045 could favorably ameliorate the diabetic state of the recipients xenotransplanted with the bioartificial pancreas, leading to an improved glucose tolerance and longer xenograft survival.     

Effects of strong pulsed magnetic fields on the cardiac activity ofan open chest dog

The heart of an open chest dog was stimulated by strong magnetic fields which were damped sinusoidal pulses with the one-cycle period of 1.47 ms. Stimulation effects were detected by electrocardiograph (ECG) and arterial blood pressure as a function of the strength of the field, the triggering point in the cardiac cycle, and the position of a stimulating coil. The threshold for arrhythmias was a minimum for the stimuli triggered at the apex of the T wave and on the P wave in the ECG. Premature ventricular and premature atrial contractions occurred according to whether the coil was placed over the ventricles or the atria. Ventricular defibrillation can not be attained by the magnetic stimulus with the flux density of 9.2 T which was the maximum field used