The solution polycondensation of 3,3′ ‐diaminobenzidine tetrahydrochloride with aromatic dicarboxylic acid derivatives in polyphosphoric acid was found to give high molecular weight polyphenylenebenzimidazoles easily. Their preparation and physical properties, such as thermal stability, solubility, crystallinity, are described.
The hSNF5/INI1 gene, which encodes a subunit of the SWI/SNF family of chromatin-remodeling complexes and is located at 22q11.2, has been reported as a tumor suppressor gene inactivated in malignant rhabdoid tumors (MRTs). We analyzed this gene in varieties of pediatric solid tumors including MRTs, using the reverse transcription-polymerase chain reaction (PCR) and PCR-single strand conformation polymorphism method. We found 5 homozygous deletions, 2 truncated mutations, one missense mutation, and one silent mutation of the hSNF5/INI1 gene in 7 MRT cell lines, and one homozygous deletion, one microdeletion, one splicing acceptor site mutation, and one absence of expression in 7 fresh tumor tissues of MRT and atypical teratoid (AT)/rhabdoid tumors (RTs). Homozygous deletions were also found in one (KYM-1) of 8 rhabdomyosarcoma (RMS) cell lines. To investigate characteristics of the KYM-1 cell line, we have established KYM-1 tumors in nude mice into which KYM-1 cells were transplanted. Notably, we found that MyoD1, known as a marker for RMS, was not expressed in the KYM-1 cell line as well as MRT cell lines and fresh tumors. Histopathologic, cytogenetic, and molecular studies of the KYM-1 cell line and KYM-1 tumors in nude mice have revealed that this RMS cell line should be MRT rather than RMS. RMS-carrying aberrations of the hSNF5/INI1 gene should be reevaluated. No aberrations of this gene were found in the other 34 cell lines or 80 fresh tumor specimens except the single nucleotide polymorphisms in the 3' noncoding region. These results suggest that alterations of the hSNF5/INI1 gene were restricted to MRTs or AT/RTs in pediatric solid tumors.
Polybenzoxazoles of high molecular weight were prepared easily by the solution polycondensation of 3,3'-dihydroxybenzidine dihydrochloride or 3,3'-diamino-4,4'-dihydroxybiphenyl dihydrochloride with both aromatic and aliphatic dicarboxylic acids in polyphosphoric acid. Polybenzothiazoles were prepared from 3,3'-dimercaptobenzidine dihydrochloride and dicarboxylic acids by the same procedure.Aromatic polybenzoxazoles and polybenzothiazoles showed BR excellent thermal stability up to 450 "C. in air. They were insoluble in organic solvents. ZUSAMMENFASSUNG:Polybenzoxazole hohen Molekulargewichtes konnen leicht hergestellt werden durch Polykondensation von 3,3'-Dihydroxybenzidin-dihyclrochlorid oder 3,3'-Diamino-4,4'dihydroxybiphenyl-dihydrochlorid mit aromatischen und aliphatischen Dicarbonsauren in Polyphosphorslure. Polybenzothiazole lassen sich nach der gleichen Methode aus 3,3'-Dimercaptobenzidin-dihydrochlorid und Dicarbonsauren herstellen.Aromatische Polyhenzoxazole und Polybenzothiazole zeigen eine ausgezeichnete thermische Stabilitlt bis 450 "C in Luft. Die Polymeren sind unloslich in organischen Losungsmitteln.
SynopsisFar-infrared spectra of poly-palanines having the a-helical conformation and the ,%form structure were measured. The spectra of glycine-L-alanine copolymer, silk fibroin, and copoly-D,calanines with different D : L compositions were also measured. In addition to the bands so far reported, four bands at 190, 167, 120, and 90 cm-1 were found for the a-helix conformation and the two bands at 442 and 247 cm-1 were found for the 6 form. The 442 cm-l band consists of the parallel 432 cm-l and perpendicular 445 cm-1 bands. The 247 cm-1 band is well defined and has strong dichroism parallel to the direction of stretching. These two bands appear also for silk fibroin and glycine-L-alanine copolymer. All the far-infrared bands of copoly-D,talanines can be interpreted as a-helix bands, the three peaks at 580, 478, and 420 cm-I being ascribed to the D-residue incorporated into the right-handed a-helix or to the tresidue in the left-handed a-helix.
The study of polymerization of α,ω‐polymethylene diisocyanates, tetramethylene, trimethylene, ethylene, and methylene diisocyanate, was carried out by the use of basic catalysts and polar solvents. Soluble polymers were obtained. Structures of the polymers were determined on the basis of solubility, infrared absorption, x‐ray diffraction, and chemical reactions, especially aminolysis of the polymers. It was shown that these polymers contained heterocyclic recurring units (imidazolidone and imidazoline) in each polymer chain. Finally, a possible mechanism of this kind of cyclopolymerization is described.
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