Improvement of blood compatibility on cellulose hemodialysis membrane: IV. Phospholipid polymer bonded to the membrane surface

To improve the surface blood compatibility on a cellulose hemodialysis membrane, 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers with a phospholipid polar group were immobilized on the surface through covalent bonding. The MPC polymers had a carboxylic group, which can react with hydroxyl groups on the cellulose membrane, and were synthesized by conventional radical polymerization. The reaction between the MPC polymers and the cellulose membrane was carried out in a heterogeneous system using a condensation reagent. Surface analysis of the modified membrane by X-ray photoelectron spectroscopy revealed the immobilization of the MPC polymer on the surface. The mechanical strength and permeability for a solute of the membrane did not change even after the modification. The modified cellulose membrane was blood-compatible, as determined by the prevention of adhesion, deformation, and aggregation of platelets after contact with platelet-rich plasma. Based on these results, it is concluded that the MPC polymers may be a useful material for improving the blood compatibility of cellulose hemodialysis membranes.     

Preparation of nanoparticles composed with bioinspired 2-methacryloyloxyethyl phosphorylcholine polymer

The poly(L-lactic acid) nanoparticles immobilized with 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer, which has excellent blood compatibility, were prepared by a solvent evaporation technique using the water-soluble amphiphilic MPC polymer as an emulsifier and a surface modifier. The diameter and zeta-potential of the obtained nanoparticles strongly depended on the concentration of the MPC polymer. When the nanoparticles were prepared in 1.0 mg/ml of an MPC polymer aqueous solution, the diameter was 221 nm which was determined by atomic force microscopy and dynamic light scattering measurements. The X-ray photoelectron spectroscopic analysis indicated that the phosphorylcholine groups of the MPC unit were located at the surface of the nanoparticles, that is, the MPC polymer was immobilized on the PLA particles and the surface zeta-potential was -2.5 mV. Various hydrophobic fluorescence probes could permeate through the MPC polymer layer and adsorb on the PLA surface. The amount of bovine serum albumin adsorbed on the nanoparticles was significantly smaller compared with that on the conventional polystyrene nanoparticles. It is suggested that the nanoparticles immobilized with the MPC polymer have the potential for use as both a novel drug carrier and diagnostic reagent which can come in contact with blood components.     

Angiosarcoma arising from skeletal haemangiomatosis in an atomic bomb survivor

The authors report a unique case in which an angiosarcoma arose from skeletal haemangiomatosis in a 72 year old man. This patient had a history of atomic bomb irradiation more than 50 years ago. Radiographically, the patient had multiple sclerotic foci of benign haemangiomas in the pelvis, the sacrum, and the left femur. The patient developed a high grade angiosarcoma in the left pubic bone. It is thought that atomic bomb irradiation played an important role in the development of the malignant lesion.     

Studies on complement-potentiated neutralizing antibodies (C'-PNAb) induced in rabbits inoculated with japanese encephalitis virus (JEV). I. The nature of C'-PNAb

The C'-PNAb induced by JEV grown in porcine kidney stable (PS) cells [JEV(PS)] inactivate not only the corresponding virus, hut also Western equine encephalitis (WEE), Eastern equine encephalitis (EEE), vesicular stomatitis (VS) and Sindbis viruses grown in PS cells or primary hamster kidney (HK) cell cultures in the presence of complement. The degree of complement-potentiated neutralizing (C'-PN) ability varies for each virus. The C'-PNAb do not, inactivate these viruses grown in mouse brain, even JEV. The C'-PN activity against viruses other than JEV(PS) is completely removed by absorption with the microsomal fraction of PS or HK cells, but not of mouse brain. The antibodies in fraction IgM induced by the microsomal fraction of PS or HK cells inactivate the viruses grown in PS cells to a different degree in the presence of complement, but not viruses grown in mouse brain. The activity of C'-PNAb against JEV(PS) is reduced to 2% of the original activity by absorption with sheep red cells. After absorption, the remaining C'-PNAb are not further reduced by absorption with the microsomal fraction of PS cells, nor do they inactivate the other viruses grown on PS cells. The early rabbit hemagglutination-inhibition (HI) antibodies in fraction IgM induced by JEV(PS) could not only inhibit hemagglutination with JE, WEE, EEE, and Sindbis viruses grown on PS cells in the absence of complement, but could also facilitate HI in the presence of complement. However, they could not inhibit hemagglutination with these viruses grown in mouse brain, in the presence or absence of complement. This activity of HI could also be removed by absorption with the microsomal fraction of PS cells. These findings suggest that C'-PNAb are induced by host cell components associated with the virus, and that the early HI antibodies in fraction IgM are the same entities as C'-PNAb.     

Clinical significance of IgG4 antibody determination in children against egg white, milk, soybean and Dermatophagoides farinae]

The measurement of IgE and IgG4 antibodies against egg white, milk, soybean and Dermatophagoides farinae was performed by FAST (fluorescence allergosorbent test) using 21 serum samples obtained from non-allergic children and 160 serum samples from atopic children with bronchial asthma and/or atopic dermatitis. Their antibody levels were evaluated for any association with disease severity and for clinical significance in establishing diagnosis. It was found that children with bronchial asthma showed lower levels of IgE antibodies against egg white, milk and soybean and higher levels of IgE antibodies against Dermatophagoides farinae compared with those of children with atopic dermatitis, while both groups showed higher levels of egg white and milk-specific IgG4 antibodies compared with non-allergic children. These IgE and IgG4 antibody levels revealed a tendency to correlate with disease severity in patients with atopic dermatitis, while this was not observed in patients with bronchial asthma. The contribution percentages of IgG4 antibody determination, together with IgE antibody determination, in retrieving causal allergens were 71% for egg white, 70% for milk and 48% for soybean allergy, implying their diagnostic value in establishing clinical diagnosis.     

Preclinical evaluation of a hollow fiber silicone membrane oxygenator for extracorporeal membrane oxygenator application

A silicone membrane hollow fiber oxygenator applicable for use as an extracorporeal membrane oxygenator (ECMO) has been developed in our laboratory. This silicone hollow fiber displays astonishing mechanical stability, is barely compressible or stretchable, and assembles easily while maintaining good gas permeability. The priming volume is 140 cc with a surface area of 0.8 m2. This study evaluated the gas transfer performances and biocompatibility of the oxygenator under ECMO and CPB conditions. In vitro studies that were performed at a blood flow rate of 2 L/min, and revealed O2 and CO2 gas transfer rates of 82.35 +/- 0.56 ml/m2/L/min and 38.72 +/- 2.88 ml/m2/L/min, respectively. The commercially available Kolobow (Avecor 1500) oxygenator was used as the control, and had O2 and CO2 gas transfer rates of 53.8 +/- 0.5 ml/m2/L/min and 24.7 +/- 2.0 ml/m2/L/min. To evaluate blood trauma, Normalized Index of Hemolysis (NIH) was measured according to American Society of Testing and Materials (ASTM) standards. The NIH findings were 0.0112 g/100L at a blood flow of 1 L/min, and 0.0152 g/100L at 5 L/min. Three ex vivo experiments, using a blood flow rate of 1 L/min, were performed with venoarterial bypass, and O2 transfer rate and CO2 transfer rate of the oxygenators were well maintained. This indicates that this preclinical silicone membrane hollow fiber oxygenator has superior efficiency, less blood trauma, and is smaller when compared with the only clinically available Kolobow oxygenator.     

Polyethylene/phospholipid polymer alloy as an alternative to poly(vinylchloride)-based materials

To develop new biomaterials for making medical devices, polymer alloys composed of a phospholipid polymer, poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), and polyethylene (PE) were prepared. The PE/PMPC alloy membrane could be obtained by a combination of solution mixing and solvent evaporation methods using xylene and n-butanol mixture as a solvent. Moreover, thermal treatment was applied to improve the mechanical properties of the PE/PMPC alloy membrane. In the PE/PMPC alloy membrane, the PMPC domains were located not only inside the membrane but also at the surface. Surface analysis of the PE/PMPC alloy membrane with X-ray photoelectron spectroscopy, wettability evaluation, and dynamic contact angle measurements revealed that the phospholipid polar groups in the PMPC covered the surface even after thermal treatment. Blood compatibility tests with attention to platelet adhesion and change in morphology of adhered platelets showed that the PE/PMPC alloy membrane had excellent platelet adhesion resistance. We finally concluded that the PE/PMPC alloy could be used as biomaterials instead of poly(vinyl chloride)-based materials.     

Dependence of the anterior olfactory area self-stimulation upon the lateral hypothalamic area

The functional relation between the anterior olfactory area (AO) and the lateral hypothalamic area (LH) was examined in a self-stimulation situation. Bar-pressing responses for AO sitmulation were suppressed by unilateral injection of procaine, and enhanced by glutamate, into LH. Neither procaine nor glutamate injected into AO had any influence upon LH self-stimulation. It is unlikely that the procaine effect was due to motor disturbance because similar injection of procaine into LH did not disturb the performance of a one-way avoidance task. It appears that the rewarding effect of AO stimulation is dependent upon the excitation of the more caudal structures including LH.     

Apoptosis signaling pathways in lung diseases

Evidence that apoptosis plays an important role in the pathophysiology of lung diseases has been accumulated. Apoptosis signaling is classically composed of two principle pathways. One is a direct pathway from death receptor ligation to caspase cascade activation and cell death. Death receptor ligation triggers recruitment of the precursor form of caspase-8 to a death-inducing complex, through the adaptor protein FADD, which leads to caspase-8 activation. The other pathway triggered by stimuli such as drugs, radiation, infectious agents and reactive oxygen species is initiated in mitochondria. After cytochrome c is released into the cytosol from the mitochondria, it binds to Apaf1 and ATP, which then activate caspase-9. Recently, endoplasmic reticulum has also been shown to be the organelle to execute apoptosis. Further understanding of molecular mechanisms of apoptosis and its regulation by novel drugs may lead to the development of effective strategies against lung diseases. We overview the signaling pathways of apoptosis and discuss the involvement of apoptosis in the pathophysiology of various lung diseases.     

Proliferation Kinetics of Rat Kupffer Cells after Partial Hepatectomy Immunohistochemical and UItrastructural Analysis

In an effort to settle the conflicting views on the proliferation kinetics of Kupffer cells (Kc), we performed 2/3 partial hepatectomy on rats injected with Pelikan ink. Using an anti-rat macrophage monoclonal antibody, ED 2, we evaluated the numerical changes in total, carbon-positive ED 2⁺ cells and carbon-negative ED 2⁺ cells in the portal and central area. We also analyzed the ultrastructure and peroxidase cytochemistry of various types of cells observed during regeneration. The total numbers of ED 2⁺ cells in the remaining liver increased rapidly from day 2 to 5, and the number of dividing ED 2⁺ cells reached a maximum on day 2. Thus, the numerical increase in ED 2⁺ cells corresponded to the division phase. In contrast, the carbon-labeling experiment showed a continuous increase of carbon negative ED 2⁺ cells from day 2 to 7. In the central area where division was less frequent, the proportion of carbon-positive cells decreased markedly to 50% on day 7, as against 97% in control rats. These findings suggest the possibility of an influx of carbon-negative Kc in addition to cell division. Ultrastructurally, the presence of carbon-negative "small Kc" and "immature Kc" with morphological features different from those of carbon-positive Kc was demonstrated. Such carbon-negative Kc with a high nucleus-to-cytoplasm ratio and rather few phagosomes, were not observed in control rats. Furthermore, we demonstrated two types of possible precursor cell, i.e. "transitional" forms between monocytes and Kc, and "immature macrophages". The former showed peroxidase activity in some lysosomes as well as in the rough endoplasmic reticulum and nuclear envelope. Our result indicated that the proliferation kinetics of Kc depend upon both local proliferation and influx.