A case of macrocystic cervical neurinoma diagnosed by MRI with Gd-DTPA

The authors report a rare case of a large cystic cervical neurinoma. A 45-year-old female was admitted to our clinic because of motor weakness of the right upper extremity, numbness of the right fingers and right posterior cervical pain. Metrizamide CT myelography demonstrated the outline of a low density mass. MRI showed a mass revealing low signal intensity on T1-weighted image, high signal intensity on T2-weighted image and marginal enhancement on contrast image with Gd-DTPA. The mass which was diagnosed as cystic tumor, was located in the intradural extramedullary space between C4 to C5 segments. After C4 through C5 laminectomy, the tumor was found to originate from the C5 anterior motor root. The tumor consisted mostly of a cystic part with a very thin solid compartment beneath the capsule. Postoperative course of the patient was uneventful. Although spinal neurinoma is one of the most common spinal tumors, an almost completely degenerated large cystic spinal neurinoma is extremely rare. MRI with Gd-DTPA was useful for the diagnosis of the cystic neurinoma by clearly enhancing the margin of the tumor.     

Formation of dityrosine and other fluorescent amino acids by reaction of amino acids with lipid hydroperoxides

Formation of fluorescence by the reaction of various amino acids with lipid hydroperoxides,i.e., linoleic acid 13-monohydroperoxide, methyl linoleate 13-monohydroperoxide and phosphatidylcholine hydroperoxide, in the presence of methemoglobin was investigated. Two types of fluorescence were produced: fluorescent dityrosine (3,3′-dityrosine) from tyrosine, and unidentified fluorophores with α- and ε-amino groups of various amino acids. While the former was stable after treatment with borohydride, the latter fluorophores were readily destroyed. The rate of dityrosine formation was rapid, and the yield of dityrosine was dependent on the concentrations of tyrosine and the lipid hydroperoxides. Butylated hydroxytoluene and tocopherol inhibited the formation of dityrosine, but did not affect the formation of fluorophores on the amino groups. Dityrosine appears to be formed by radical reaction of the lipid hydroperoxides, while the other fluorophores seem to be created by nonradical mechanisms.     

Effects of Environmental Temperature and Compression Energy on Polymorphic Transformation During Tabletting

The effects of temperature on the polymorphic transformation and the compression of chlorpropamlde forms A and C during tabletting were investigated by X-ray diffractometry. The X-ray diffraction profiles of the sample powders deagglomerated after compression were recorded to calculate the degree of polymorphic transformation. A single punch eccentric tabletting machine equipped with two load cells (upper and lower punches) and with a noncontact displacement transducer was used to measure the compression stress, energy and distance between punches. A heater and a liquid nitrogen pool were mounted on the die of the tabletting machine, and the die temperature was controlled with a thermocontroller. Two types of compression methods, multi-tabletting at room temperature and single tabletting at 0-45°C, were used in the present study. In the first method, the stable form A or metastable form C was loaded in to the die and the sample was compressed with a compression stress of 196 MPa. Compression was repeated from 1 to 30 times. The results for forms A and C suggested that both forms were mutually transformed, and that the content of forms A and C reached equilibrium above 100 J/g of compression energy after more than 10-times compression. After 30-times compression, the content of A, C, and the noncrystalline solid form were almost constant at about 45%, 25% and 30%, respectively. The compression energy was estimated to be 500-600 J/g. In the second method, single tabletting at 0° and 45°C, the amount of form C transformed from form A at 45°C was about two times larger than that at 0°C at the same compression energy. The amount of form A transformed from form C at 45°C was almost the same as that transformed at 0°C. This suggests that the mechanochemical stability of form A was affected by compression temperature, while that of form C was independent of temperature. The crushing strength (CS) of from A tablet was about two times higher than that of form C even at the same porosity. The relationships between log (CS) of form A tablets compressed at 0 or 45°C and porosity showed straight lines with the same slope, but the slope for form C tablets compressed at 45°C was smaller than that for those compression at 0°C. From these results it appears that the transformation mechanism of forms A and C during compression was as follows: Form A or C was converted to a noncrystalline solid by mechanical energy, and then the solid was transformed into form A or C. The transformation of every form was affected by the environmental temperature.     

Age-related accumulation of phosphatidylcholine hydroperoxide in cultured human diploid cells and its prevention by α-tocopherol

The levels of phosphatidylcholine hydroperoxide in serially cultured human fetal diploid fibroblasts at various population doubling levels were determined by high-performance liquid chromatography combined with chemiluminescence detections. This methodology utilizes a mixture of cytochromec and luminol as post-column hydroperoxide group specific luminescent reagents. The cellular hydroperoxide content increased with age from 0.34 to 27.72 pmol/10⁶ cells. At the end of the cells'in vitro lifespan (51st population doubling level), the hydroperoxide content per 10⁶ cells reached about 80 times the level found in cells of the 20th population doubling level. Supplementation of exogenous α-tocopherol to the culture medium prevented hydroperoxide accumulation, but did not extent the lifespanin vitro. The results indicate that substantial intracellular phospholipid hydroperoxide accumulation occurred in the course of aging of human fetal liploid fibroblasts.     

Synthesis of well-defined poly(styrene)-b-poly(p-tert-butoxystyrene) multiblock copolymer from poly(alkoxyamine) macroinitiator

The stepwise insertion reaction of styrene (St) and p-tert-butoxystyrene (BOSt) into poly(alkoxyamine) macroinitiator was carried out to provide well-defined poly(St)-b-poly(BOSt) multiblock copolymers. Structural confirmation of the multiblock copolymers was accomplished by NMR and IR measurements. The model reaction also supported that the monomer insertion into the macroinitiator proceeded in accordance with a living fashion.     

N，O，O′─三（对甲苯磺酰基）双（2─羟乙基）胺的合成

二乙醇胺和对甲苯磺酰氯在三乙胺存在下，反应生成Ｎ，０，Ｏ′－三（对甲苯磺酰基）双（２－羟乙基）胺，产率９３％。从反应混合物中分离得副产物Ｎ，Ｏ－二（对甲苯磺酰基）双（２－羟乙基）胺。     

Application of polymerizable surfactant in the preparation of polystyrene/nano-Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> composite

Monooctadecyl maleate, as a polymerizable surfactant, was synthesized by the mono-esterification of maleic anhydride and octadecanol, and was utilized to surface-modify nano-Fe₃O₄ particles. A polymerizable magnetic fluid was obtained by directly dispersing modified nano-Fe₃O₄ particles into styrene monomer, and the polystyrene/nano-Fe₃O₄ composite was prepared through free radical polymerization of polymerizable magnetic fluid. The structure and dispersion status in different dispersion phases of modified nano-Fe₃O₄ particles were studied by Fourier transform infrared (FTIR) spectrometry, X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The experimental results show that the nano-Fe₃O₄ particles modified by monooctadecyl maleate with the size of about 7–10 nm can be uniformly dispersed into styrene and fixed in the composite during the procedure of polymerization. Thermogravimetric analysis (TGA) and vibrating sample magnetometry (VSM) indicate that the thermal stability of polystyrene/nano-Fe₃O₄ composite is improved compared to that of pure polystyrene, and the composite is a sort of superparamagnetic materials.