Role of a signal transduction pathway which controls disassembly of microfilament bundles and suppression of high-molecular-weight tropomyosin expression in oncogenic transformation of NRK cells

Role of disassembly of microfilament bundles and suppression of high-molecular-weight tropomyosin (TM) expression in growth factor- and various oncogene-induced transformation was studied by using NRK cells and its transformation-deficient mutants. In NRK cells which show a transformed phenotype by treatment with EGF and TGF-beta, cellular stress fibers became dissociated by EGF or EGF and TGF-beta combination, whereas TGF-beta alone caused thicker appearance of stress fibers. Accompanying these changes, the expression of TM isoforms 1 and 2 was suppressed by treatment with EGF or EGF and TGF-beta, but elevated by TGF-beta with similar time courses. On the other hand, the transformation-deficient mutant cell lines, 39-1 and 39-3, did not show the transformed phenotypes by treatment with EGF and TGF-beta. Neither EGF nor EGF and TGF-beta combination affected cellular stress fibers and expression of TM isoforms 1 and 2 in both mutant lines. The relationship between the formation of stress fibers and the expression of TM isoforms was consistent in NRK cells, the mutant lines and their various oncogene-expressing sublines under various culture conditions. NRK cells overexpressing exogenous mouse TM isoform 2 showed markedly decreased susceptibility to EGF-induced dissociation of stress fibers and decreased anchorage-independent growth potential in the presence of EGF and TGF-beta. These results indicate that the transformation-deficient NRK mutant lines, 39-1 and 39-3 have defects in an EGF signal transduction pathway which induces suppression of high-molecular-weight TM expression and disassembly of microfilament bundles and suggested that the activation of the pathway is important for morphological transformation and oncogenic growth in growth factors- and various oncogene-induced transformation of NRK cells.     

chpA and chpB, Escherichia coli chromosomal homologs of the pem locus responsible for stable maintenance of plasmid R100

The pem locus is responsible for stable maintenance of plasmid R100 and consists of two genes, pemI and pemK. The pemK gene product is a growth inhibitor, while the pemI gene product is a suppressor of this inhibitory function. We found that the PemI amino acid sequence is homologous to two open reading frames from Escherichia coli called mazE and orf-83, which are located at 60 and 100 min on the chromosome, respectively. We cloned and sequenced these loci and found additional open reading frames, one downstream of each pemI homolog, both of which encode proteins homologous to PemK. The pem locus homolog at 60 min was named chpA and consists of two genes, chpAI and chpAK; the other, at 100 min, was named chpB and consists of two genes, chpBI and chpBK. The distal portion of chpBK was found to be adjacent to the ppa gene that encodes pyrophosphatase, whose map position had not been previously determined. We then demonstrated that the chpAK and chpBK genes encode growth inhibitors, while the chpAI and chpBI genes encode suppressors for the inhibitory function of the ChpAK and ChpBK proteins, respectively. These E. coli pem locus homologs may be involved in regulation of cell growth.     

Partial colpocleisis for vesicovaginal fistulas

Four patients with a vesicovaginal fistula were operated upon transvaginally using the Latzko technique of partial colpocleisis. In 3 of the 4 patients, the fistulas had been formed after total hysterectomy for myoma uteri or endometriosis. The periods from fistulization-to-surgery intervals in these 3 patients were 4 months, 12 months, and 4 years and 4 months, respectively. The fistulas in the remaining one patient had been formed after forceps delivery. The patient underwent surgery 8 days after delivery. An indwelling catheter was retained for 3 to 14 days after surgery. The 4 patients were all cured of vesicovaginal fistulas after a single operation. This paper describes our partial colpocleisis technique and discusses its clinical utility. The partial colpocleisis has the advantages of dispensing with such procedures as fistula excision, fistula opening suture, and suturation of the bladder musculature, and of closing the fistulas using a demucosated vaginal wall. Having minimal surgical invasiveness and being easy to perform and reliable, the technique appears to be excellent for coping with vesicovaginal fistulas.     

Primary non-Hodgkin lymphoma of the sinonasal cavities: correlation of CT evaluation with clinical outcome

PURPOSE: To determine retrospectively the primary site of origin of sinonasal lymphomas with computed tomography (CT) and correlate the CT findings with histologic phenotype and clinical outcome. MATERIALS AND METHODS: In 24 patients with stage I and II non-Hodgkin lymphomas of the sinonasal cavities, the CT appearances and clinical data were reviewed retrospectively. RESULTS: The sites of primary tumor determined at CT were the nasal cavity in 13 patients, the ethmoidal sinus in three patients, and the maxillary sinus in eight patients. B-cell lymphomas were found mainly in the maxillary sinus, while T-cell lymphomas were found in the nasal cavity and ethmoidal sinus (P < .005). The 5-year survival rates in relation to the primary site of the tumor were 64% for the nasal cavity, 50% for the ethmoidal sinus, and 100% for the maxillary sinus (P = .26). CONCLUSION: Patients with B-cell primary lymphoma of the maxillary sinus tended to have a good prognosis in contrast to those with T-cell lymphomas that originated from midline structures. The primary site determined at CT appears to be correlated with the histologic phenotype and clinical outcome.     

Ultrastructural study on cytotoxic effects of cyclosporine A in spermiogenesis in rats

Cyclosporine A (CsA) is known to have testicular toxicity, leading to male infertility. The occurrence of numerous anomalous spermatids and residual bodies in the epididymal ducts of rats treated with CsA was observed in our previous studies. To examine the fine structural changes of impaired spermiogenesis induced by CsA, rats were treated s.c. with 40 mg/kg/day CsA for 2 weeks. Desquamation of round spermatids still surrounded by a slender Sertoli cell cytoplasm was occasionally observed. A prominent change in the seminiferous tubules was an occurrence of numerous residual bodies containing one or more flagella. They were not phagocytosed by the Sertoli cell, and accumulated in the epididymal ducts. Cellular components in the epididymal lumen included degenerating round spermatids and abnormal spermatozoa and residual bodies. Although separation of the head from the tail of the spermatozoa was rarely seen, various kinds of abnormalities of flagella were frequently encountered; compact aggregation of numerous flagella in a single spermatozoon or residual body, disarrangement of mitochondrial or fibrous sheath with outer dense fibers, and fusion of flagella with a single intervening mitochondrial layer. These findings indicate that CsA gives rise to toxic effects on the spermiogenesis by impairing directly the spermiogenic cell development and by impeding Sertoli cell function including a reduction of its phagocytic activity.     

A multi‐agent approach to unit commitment

This paper proposes a multiagent system to power system unit commitment problems. Multiagent is a new paradigm for developing software applications. Coordinating the behavior of autonomous agents is a key issue in agent‐oriented programming techniques today. Recently, agents are being used in an increasingly wide variety of applications, ranging from comparatively small systems such as E‐mail filters to large, open, complex systems such as air traffic control. Though some agent frameworks have been proposed in the power system field, the number of studies is limited. In this paper, we developed a power system unit commitment application by multiagent architecture. Our multiagent system has the following characteristics: (1) The system consists of a single facilitator agent, two mobile agents, and one or more generator agents which are elements of power system network. (2) The facilitator agent is developed to act as a manager for the process by using the singleton design pattern. The mobile agents migrate to generator‐agents to increase or decrease their power generations. The generator agents have their operational data. (3) Message object is developed to communicate between the agents using KQML‐like object. The proposed approach is applied to a simple model system, and the results show that the multiagent system is an efficient decentralized approach for solving power system unit commitment problems. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(2): 41–47, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10057     

Mechanochemical polymerization in mixtures of diallyl terephthalate and distilled water by ultrasonic irradiation

Summary Mechanochemical polymerization in systems of diallyl terephthalate-distilled water has been studied by ultrasonic irradiation at 90°C. An additional effect of distilled water on mechanochemical polymerization of diallyl terephthalate was investigated. When a 1.2 wt % distilled water solution, the conversion of poly(diallyl terephthalate) was the greatest and the initial rate of the polymerization R _p was 1.3x10^-5 mol/l sec. This polymerization proceeded by a radical mechanism and the primary radicals produced from water molecules by ultrasonic waves. In addition, changes in the iodine value and the weight-average molecular weight of the resulting polymers were proved.     

Plastic optical fibers with fluoroalkyl methacrylate copolymer as their core

Novel plastic optical fibers having a core made of a crosslinking copolymer containing mainly fluoroalkyl methacrylate (FMA–POFs) were fabricated and their optical properties were analyzed. In the visible wavelength region, attenuation losses of as-manufactured FMA–POFs were low and their loss spectra were similar to that of the plastic optical fiber whose core was made of methyl methacrylate copolymer (MMA–POF). But after heating at 160°C in air, increases in attenuation losses of FMA–POFs were about 10 times smaller than that of the MMA–POF. FMA–POFs had an optical window at 780 nm. There was hardly any change in loss at 780 nm compared with the loss increase at 660 nm. This indicated that FMA–POFs would be applicable to optical communications at 780 nm in the near-IR region.     

Diode laser pumped Er/sup 3+/ fibre laser operation between 2.7-2.8 mu m

CW laser operation in the 2.7-2.8 mu m region has been observed in Er/sup 3+/ doped fluorozircoaluminate glass fibres by diode laser pumping at 0.8 mu m. An absorbed threshold power of 10 mW and an output laser power of 2.1 mW with a slope efficiency of 8% were obtained.<>