Malignant tumors of the kidney, brain, and soft tissues in children and young adults with the tuberous sclerosis complex

BACKGROUND: The tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by seizures, mental retardation, and benign tumors of the brain, heart, skin, and kidney. Malignant tumors also can occur in patients with tuberous sclerosis, particularly in the kidney, although they occur less frequently than benign tumors. The types of malignancy that occur in TSC have not been characterized fully. METHODS: Clinical and pathologic features of 8 malignant tumors from 6 TSC patients ranging in age from 22 months to 21 years are reviewed. Six tumors were renal, one was from the inguinal region, and one was from the brain. The tumors were analyzed for loss of heterozygosity (LOH) in the chromosomal regions of the TSC1, TSC2, and VHL genes. RESULTS: Three patients (ages 7, 8, and 20 years) had renal cell carcinomas (RCCs). Two of these patients had multifocal RCCs. All three patients with RCC also had prominent multifocal dysplasia of renal cyst epithelium. Two patients (ages 20 and 21 years) had malignant angiomyolipomas (1 renal and 1 inguinal). One patient (age 22 months) had a Grade 4 giant cell astrocytoma (glioblastoma multiforme). LOH in the region of the TSC2 gene was found, either in the malignant tumor or in benign tumors, in all five patients whose DNA could be analyzed. CONCLUSIONS: Children with TSC, as well as adults with the disease, are at risk for developing malignant tumors. Two types of renal malignancy occur in TSC: RCC, which appears to arise from dysplastic renal cyst epithelial cells, and malignant angiomyolipoma. Tumors cytologically similar to malignant angiomyolipomas also may occur at extrarenal sites. LOH analyses suggest that the majority of patients with TSC who develop malignant tumors have germline TSC2, rather than TSC1, gene mutations.     

A Kinetic Model of Degradation of Phenol in Water by Direct Contact of Gas Nonpulsed Corona Discharge

Reaction byproducts from degradation of aqueous phenol by contact of gas d.c. corona discharge with treated water were analyzed by liquid chromatography. According to the retention time, three byproducts, pyrocatechol, hydroquinone, 1,4‐benzoquinone, were identified. Also, acetic acid was detected as a final relatively stable byproduct by gas chromatography. A simple reaction model in which relevant elementary reactions are assumed to be first order was proposed to correlate the practical behavior of degradation processes.     

Porous Ceramic Filters Produced by Hot Isostatic Pressing

Porous TiO₂ ceramics were produced by capsule-free hot isostatic pressing (HIPing) and were evaluated by measuring gas permeability and pore size distribution. In comparison to conventionally sintered TiO₂, the HIPed TiO₂ has a higher permeability and narrower pore size distribution. The differences are caused by the effects of high-pressure gas during sintering.     

Characterization of Secretory Phospholipase A<Subscript>2</Subscript> with Phospholipase A<Subscript>1</Subscript> Activity in Tobacco, <Emphasis Type="Italic">Nicotiana tabacum</Emphasis> (L.)

A cDNA encoding protein with homology to plant secretory phospholipase A₂ (sPLA₂), denoted as Nt1 PLA₂, was isolated from tobacco (Nicotiana tabacum). The cDNA encodes a mature protein of 118 amino acid residues with a putative signal peptide of 29 residues. The mature form of Nt1 PLA₂ has 12 cysteines, Ca²⁺ binding loop and catalytic site domain that are commonly conserved in plant sPLA₂s. The recombinant Nt1 PLA₂ was expressed as a fusion protein with thioredoxin in E. coli BL21 cells and was purified by an ion exchange chromatography after digestion of the fusion proteins by Factor Xa protease to obtain the mature form. Interestingly, Nt1 PLA₂ could hydrolyze the ester bond at the sn-1 position of glycerophospholipids as well as at the sn-2 position, when the activities were determined using mixed-micellar phospholipids with sodium cholate. Both activities for the sn-1 and -2 positions of glycerophospholipids required Ca²⁺ essentially, and maximal activities were found in an alkaline region when phosphatidylcholine, phosphatidylglycerol or phosphatidylethanolamine was used as a substrate. The level of Nt1 PLA₂ mRNA was detected at a higher level in tobacco flowers than stem, leaves and roots, and was induced by salicylic acid.     

Influence of film structure on gas barrier properties of SiOxNy films

SiO_xN_y thin films were deposited on PET substrates by dc magnetron sputtering under various nitrogen gas flow ratios, and the influence of the nitrogen gas flow ratio on the gas barrier performance was examined on the basis of local structure of SiO_xN_y. The surface morphology of the films was evaluated by FE-SEM and AFM observations. The local structure of SiO_xN_y was determined by FT-IR analysis and measurement of refractive index. No obvious macro-defects, such as pinholes, were observed in the films and the surface morphology of all samples was similar. The film density increased with increasing nitrogen gas flow ratio during the deposition process. However, the gas barrier performance decreased with increasing nitrogen gas flow ratio. On the basis of FT-IR analysis, it was determined that the structure of the SiO_xN_y film was a random bonding model (RBM) structure and an increase in the nitrogen gas flow ratio caused an increase in hydrogen termination in the Si-O-N network. The degradation of gas barrier performance at a high nitrogen gas flow ratio is due to the discontinuous Si-O-N network caused by the hydrogen termination.     

The novel functional nucleic acid iRed effectively regulates target genes following cytoplasmic delivery by faint electric treatment

An intelligent shRNA expression device (iRed) contains the minimum essential components needed for shRNA production in cells, and could be a novel tool to regulate target genes. However, general delivery carriers consisting of cationic polymers/lipids could impede function of a newly generated shRNA via electrostatic interaction in the cytoplasm. Recently, we found that faint electric treatment (fET) of cells enhanced delivery of siRNA and functional nucleic acids into the cytoplasm in the absence of delivery carriers. Here, we examined fET of cells stably expressing luciferase in the presence of iRed encoding anti-luciferase shRNA. Transfection of lipofectamine 2000 (LFN)/iRed lipoplexes showed an RNAi effect, but fET-mediated iRed transfection did not, likely because of the endosomal localization of iRed after delivery. However, fET in the presence of lysosomotropic agent chloroquine significantly improved the RNAi effect of iRed/fET to levels that were higher than those for the LFN/iRed lipoplexes. Furthermore, the amount of lipid droplets in adipocytes significantly decreased following fET with iRed against resistin in the presence of chloroquine. Thus, iRed could be a useful tool to regulate target genes following fET-mediated cytoplasmic delivery with endosomal escape devices.     

Analysis of reflector antenna system including frequency selectivesurfaces

Frequency selective surfaces (FSS) are often used in spaceborne applications of reflector antennas because of their ability to allow multiple feeds to utilize the same reflector dish. The problems inherent in evaluating the FSS separately from the reflector system are discussed. A method of integrating the FSS effects into the reflector system analysis is presented. An example is given for the proposed Advanced Tracking and Delay Relay Satellite System (ATDRSS) single-access triband reflector antenna     

A PWM rectifier/inverter system capable of suppressing both harmonics and EMI

This paper proposes a new PWM rectifier/inverter system that is capable of suppressing not only supply harmonic currents but also electromagnetic interference (EMI). The conversion system consists of a PWM rectifier and inverter, and an active common‐noise canceler (ACC) which has been proposed by the authors. The ACC developed for this system is characterized by the sophisticated connection of a common mode transformer which can compensate for common mode voltages produced by both the PWM rectifier and inverter. As a result, the size of the common mode transformer can be reduced to one‐third, compared with the previously proposed ACC. A prototype PWM rectifier/inverter system (2.2 kW) has been implemented and tested. Some experimental results show reduction characteristics of the supply harmonic current and EMI. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(4): 59–68, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10062