Anionic polymerization of monomers containing functional groups, 14. Anionic polymerizations of aryl 4‐vinylbenzoates

Anionic polymerizations of phenyl ( 2a ), 4‐methoxyphenyl ( 2b ), 2‐methylphenyl ( 2c ), 2‐tert‐butylphenyl ( 2d ), 3,5‐di‐tert‐butylphenyl ( 2e ), 2,6‐dimethylphenyl ( 1f ), 2,6‐diisopropylphenyl ( 2g ), 2,6‐di‐tert‐butyl‐4‐methylphenyl ( 2h ), and 2,6‐di‐tert‐butyl‐4‐methoxyphenyl ( 2i ) 4‐vinylbenzoates were carried out in THF at –78°C with diphenylmethylpotassium and oligo(α‐methylstyryl)lithium and ‐dipotassium. No apparent polymerizations of 2a – 2e occurred probably due to the inherent side reactions such as nucleophilic attack of the anionic initiators toward the ester carbonyl groups. On the other hand, the polymerizations of 2f – 2i , the monomers possessing bulky aryl ester substituents, certainly proceeded to afford the polymers in quantitative yields. The molecular weight distribution (MWD) of poly( 2f ) was broad (M_w/M_n = 1.3–1.8), indicating partial side reactions during the course of the polymerization. By contrast, the resulting poly( 2g – 2i ) possessed narrow MWDs (M_w/M_n = 1.1) and predicted molecular weights based on the molar ratios between monomers to initiators. It was thus demonstrated that the steric hindrance around the ester carbonyl group was essential to obtain polymers having well‐defined chain structures via controlled anionic polymerizations of aryl 4‐vinylbenzoates. Novel tailored block copolymers, polyisoprene‐block‐poly( 2h ), poly( 2h )‐block‐polystyrene‐block‐poly( 2h ), poly(tert‐butyl methacrylate)‐block‐poly( 2h ), and poly( 2h )‐block‐poly(2‐isopropenylbenzoxazole) were synthesized by the sequential copolymerization of 2h and the corresponding comonomers. It was elucidated from the results of block copolymerization that anionic polymerizability of 2h was apparently higher than that of styrene because of the electron‐withdrawing effect of the COOAr substituent.     

Moving Mesh Method for Reconstructing Some Spread Sources in the Brain

The purpose of this paper is to propose a new algorithm for the analysis of biomagnetic field data obtained from magnetoencephalography (MEG) measurements. This new method overcomes two major problems faced by the current method of data analysis. The first problem is the need to determine the number of sites of brain activity before calculations can be performed. The second problem is inability of the analysis to provide any information regarding the volume of the brain activity. The new data analysis method, called the Moving Mesh Method (MMM), is capable of analyzing MEG data without the need to determine the number of sources beforehand. In addition, the MMM determines the location of brain activity as a three dimensional volume, instead of as a point source of activity. The MMM uses an iterative method of calculating the position of the sources to achieve greater accuracy, and a regularized g-inverse matrix to stabilize its solution. The feasibility of the MMM was examined by two methods. First, a computer simulation was used to confirm the MMM's capability to analyzing MEG data. In the second experiment, the MMM was applied to analyze somatosensory evoked fields obtained using a new imaging system (Shimadzu Biomagnetic Imaging System, Model-100). From the interpretation of the results, we have concluded that the MMM is a feasible method of biomagnetic data analysis.     

Preparation of a bioartificial kidney using tubular epithelial cells, and an evaluation of Na+ active transport and morphological changes

We intend to develop a bioartificial kidney using tubular epithelial cells and artificial membranes, and to evaluate the reabsorptive function of the confluent layers. Madin-Darby canine kidney (MDCK) cells were cultured on a nucleopore polycarbonate membrane for up to 4 weeks after confluence to examine the influence of culture period on their properties, such as the localization of Na⁺/K⁺-ATPase and active Na⁺ transport. The results were as follows. Ouabain-sensitive Na⁺ active transport declined at 3 to 4 weeks after confluence in each matrix. The localization of Na⁺/K⁺-ATPase indicated depolarization in the cell membrane 3 to 4 weeks after confluence. Prolongation of the culture period increased the formation of an upheaving cell mass after the formation of the confluent monolayer. Scanning electron microscopy revealed fewer microvilli and more flat cells after 3 to 4 weeks of confluency. We conclude that the decline of Na⁺ active transport in the MDCK cells was due to both the formation of multilayers and a decline of cell function throughout the long period of culture following the formation of the confluent monolayers. Further study for selection of membrane material, the extracellular matrix, and species of cells should be continued. Laboratories for Structure and Function Research Department of Physiology     

In vivo evaluation of a new surfactant polymer coating mimicking the glycocalyx of endothelial cells

The purpose of this study was to demonstrate that a proprietary surfactant polymer (SP) coating does not adversely affect the hemodynamic performance of cardiopulmonary bypass (CPB) or gas exchange in oxygenators. The new coating was applied to a CPB circuit including cannulae, reservoir, oxygenator, and blood pump implanted into 12 pigs, divided into groups with either coated or noncoated pumps. CPB flow was maintained at a fixed level of approximately 2.4 L/min for 6 hours with full heparinization. Hemodynamic data and pump performance were recorded every hour, and blood samples were taken every 2 hours. After sacrifice, the CPB circuit and major organs were macroscopically examined. There was no significant difference in the oxygen transfer rate between the two groups. The coating did not adversely affect oxygenator inlet or outlet pressures. There was no significant difference between the two groups in microthrombi seen in the oxygenators. No thromboemboli were noted in the major organs on gross or histologic examination. In conclusion, this new SP coating did not decrease gas exchange performance, and its biocompatibility evaluations revealed no differences between coated and noncoated groups under aggressive heparin use.     

Mps3 SUN domain is important for chromosome motion and juxtaposition of homologous chromosomes during meiosis

In budding yeast, Mps3 is essential for duplicating the spindle pole body (SPB) and is critical for promoting chromosome motion during meiosis. It is a member of the SUN (Sad1-Unc-84) domain family of proteins that localizes to the inner nuclear envelope (NE) in many eukaryotic organisms and preferentially localizes to the SPB in vegetative growth; in meiotic prophase I, it redistributes to many sites within the NE. We constructed an mps3 mutant, mps3-sun, which completely lacks the SUN domain. Surprisingly, the mps3-sun mutation does not disrupt SPB duplication or Mps3 localization to the NE in meiosis. However, it confers several defects during meiotic prophase I including reduced chromosome motion, premature synapsis between homologous chromosomes, and reduced levels of closely juxtaposed homologous loci in pachytene. These findings suggest that in meiosis, the Mps3 SUN domain is important for modulating chromosome motion events that act in meiotic chromosome juxtaposition and by extension, promoting proper morphogenesis of the synaptonemal complex.     

Germinal center B-cell-like diffuse large B-cell lymphoma of the duodenum is associated with t(14;18) translocation

Diffuse large B-cell lymphoma (DLBCL) rarely involves the duodenum, and its clinicopathological characteristics have not been well elucidated. We performed clinicopathological examinations and identified 15 patients with duodenal DLBCL using 18 gastric or colonic DLBCL as a control. Eleven of the 15 patients (73%) were subclassified by immunohistochemical analysis according to the Choi algorithm as germinal center B-cell-like (GCB) type, whereas the 18 control gastric and colonic DLBCL were predominantly subclassified as activated B-cell-like (ABC) type. The classifications according to organ involvement were statistically significant (P= 0.011 and P= 0.035). Macroscopically, the GCB lesions were varied, while all ABC lesions were ulcerative. Fluorescence in situ hybridization analysis revealed a higher frequency of t(14;18) translocation in patients with duodenal DLBCL (3 of 13) as compared with non-duodenal gastrointestinal tract DLBCL (0 of 18), however, the difference was not significant (P = 0.064). Furthermore, the three patients with t(14;18) translocations were classified as GCB. In addition, overall survival of patients was statistically different between those with and without t(14;18) translocation (P= 0.040). In conclusion, duodenal DLBCL predominantly exhibits GCB-type tumors and the frequency of t(14;18) translocation appears to be higher in duodenal GCB-type DLBCL compared to non-duodenal tumors.     

Novel hybrid mesh surgery combines sacrocolpopexy with transvaginal mesh placement for pelvic organ prolapse

Mesh surgeries, such as sacrocolpopexy and transvaginal mesh surgery, are commonly used to treat pelvic organ prolapse. Although mesh surgeries have a high success rate, they are unsuitable for some patients. For a patient with pelvic organ prolapse and highly calcified multiple fibroids, we performed hybrid sacrocolpopexy combined with transvaginal mesh surgery with a method modified for the patient's condition. Three months after surgery, the results were highly satisfactory. This approach is simple, secure, and versatile for patients who are not good candidates for conventional mesh surgeries. This novel hybrid mesh surgery is an option for treating various types of pelvic organ prolapse.     

Ventricular fibrillation associated with early repolarization in a patient with thyroid storm

We present a case of a 69-year-old male who was hospitalized for the treatment of thyroid storm due to Grave’s disease, who presented with unexpected ventricular fibrillation (VF). The possible etiology was early repolarization (ER), characterized by J-point elevation in inferior and posterolateral leads, unmasked by the attenuation of beta-adrenergic effect with normalization of thyroid hormones and following the administration of a beta-blocker. Our case focuses attention on the occurrence of VF in a patient with ER during the treatment of hyperthyroidism, which to our knowledge is the first such report.