Interleukin-1 beta-converting enzyme mediates cisplatin-induced apoptosis in malignant glioma cells

Increasing the susceptibility of tumor cells to apoptotic cell death following chemotherapy is of importance to the outcome of cancer treatment. Although the tumor suppressor gene p53 is required for efficient induction of apoptosis by chemotherapeutic agents, it is not the only apoptosis mediator gene. The molecular mechanisms mediating apoptosis following chemotherapy via p53-dependent or p53-independent pathways remain unclear. We show here that cis-diamminedichloroplatinum (cisplatin) induces the expression of interleukin-1 beta-converting enzyme (ICE), a mammalian homologue of the Caenorhabditis elegans cell death gene ced-3, in murine and human malignant glioma cells during apoptosis regardless of their p53 status. Furthermore, overexpression of the murine ICE gene induces apoptosis in these tumor cells. The apoptosis induced by cisplatin treatment or murine ICE overexpression can be suppressed by the tetrapeptide ICE inhibitor Ac-YVAD-CMK or the apoptosis inhibitors bcl-2 or bcl-2-related bcl-XL gene. These findings suggest that ICE may mediate apoptosis induced by chemotherapy, and its induction could represent a novel approach for the effective treatment of malignant glioma.     

Creation of Ultra-precision Microstructures with High Aspect Ratios

In recent years, ultra-precision micromachining technology has been used in a variety of fields such as optical instruments, electronic devices, medical equipments, etc. At present, it is essential to meet the requirement of producing various shapes, one of which is a structure with a high aspect ratio. Such structures are applied, for example, to a shaft of micro robot, a long part of microactuator and micromachine, a microneedle for syringe, etc. However, due to its fragile nature, it is extremely difficult to fabricate the structure with a high aspect ratio since it is easily damaged during cutting. It is intended to produce micro towers with high aspect ratios by applying the ultra-precision milling technology using a single crystal diamond cutting tool. The method enables accurate creation of a variety of microstructures with high aspect ratios. In addition, the study also proposes a new machining method to create microneedle arrays, avoiding the contact of cutting edge with already machined parts again. As a result, it is concluded that the proposed method has the potential of producing a variety of microstructures with high aspect ratios.     

Molecular cloning and characterization of rat lin-10

In Caenorhabditis elegans, the vulval induction is mediated by tyrosine kinase receptor/Ras signal transduction pathway composed of the lin-3, let-23, and let-60 products. In addition to these gene products, the lin-2, lin-7, and lin-10 products are also implicated in this pathway. Lin-2 encodes a MAGUK and lin-7 encodes a small protein with one PDZ domain. The lin-10 product has no homology to known proteins. Here, we have cloned a rat homologue of the lin-10 product and characterized it. Rat lin-10 is ubiquitously expressed in various rat tissues and distributed in both the cytosol and membrane fractions. In brain, however, rat lin-10 is distributed only in the membrane fraction and enriched in the synaptic plasma membrane and postsynaptic density fractions. These results suggest that rat lin-10 is involved at least in synaptic functions in brain.     

Quasi-optical waveguide-mode converters using a pair of phase correction mirrors

This paper describes a quasi-optical method for the conversion of modes transmitted through highly oversized circular waveguides. A waveguide-mode is radiated once from a waveguide cut in the form of a radiation beam, which is then properly shaped by two curved mirrors and directed back into the waveguide. The curved mirror shapes are iteratively and automatically determined for given propagation distances using the design technique for phase correction mirrors. The proposed method gives favorable results in designing a waveguide expander/reducer, a TE₀₁-TE₀₂ mode converter, and a TE₀₁-HE₁₁ mode converter.     

Adenophostin, a potent agonist of the inositol 1,4,5-trisphosphate receptor, is useful for fertilization of mouse oocytes injected with round spermatids leading to normal offspring

Relaxin plays a major role in promoting the growth and softening of the cervix that occurs during the second half of pregnancy in the rat. There is limited evidence that prostaglandins play a role in cervical softening in mammalian species. Accordingly, this study was conducted to determine if prostaglandins mediate relaxin's effects on the rat cervix. To attain that objective, indomethacin was used to inhibit cyclooxygenase, the key enzyme in the conversion of arachidonic acid to prostaglandins. Twenty-six nonpregnant female rats were ovariectomized when they were 78 days old (day 1 of treatment). At ovariectomy (O), each rat was fitted with silicon tubing implants containing progesterone (P) and estrogen (E) in doses that provided blood levels similar to those during late pregnancy in rats. Rats were randomly assigned to three treatment groups. Group OPE controls (n = 8 rats) received 2 ml indomethacin vehicle (0.5% methyl cellulose, 0.025 Tween 80 in water) via gavage at 0900 h on days 8 and 9 and 0.5 ml relaxin vehicle (0.9% NaCl) s.c. at 6-h intervals from 1200 h on day 8 through 0600 h on day 10. Group OPER (n = 9 rats) was treated as group OPE except that 20 microg highly purified porcine relaxin was administered. Group OPERI (n = 9 rats) was treated as group OPER except that indomethacin was administered at a dose (20 mg/kg BW) that reduced cervical PGE2 levels by more than 90%. Between 0800 h and 1000 h on day 10, the cervices were removed, trimmed of fat, weighed, and placed in ice-cold Krebs-Ringer bicarbonate buffer, pH 7.5. Cervical extensibility (degree of softening) was determined within 4 h of tissue collection. Both the mean cervical wet weight and the mean cervical extensibility in the relaxin-treated group OPER rats were markedly greater (P < 0.01) than in the group OPE controls. Treatment with indomethacin did not diminish relaxin's effects on either cervical wet weight or cervical extensibility. In conclusion, this study provides evidence that relaxin's effects on cervical growth and softening in the rat are not mediated through prostaglandins.     

Radiation tolerance of type IIa synthetic diamond detector for 14 MeV neutrons

Radiation tolerance of a type IIa synthetic diamond detector was examined from irradiation of mono-energetic 14 MeV neutrons. Measurements of I–V (current–voltage) characteristics and energy spectrum for 5.486 MeV alpha particles were performed after neutron irradiation. In the I–V characteristics measurement, enhancement of rectification was observed after neutron irradiation of up to 2.0 × 10¹² n/cm². Concurrently with the enhancement of rectification, significant decrease in signal amplitude was observed in energy spectrum measurement for alpha particles. It is considered that these changes were due to increase in the concentration of defects acting as shallow energy levels in the forbidden band. For neutron irradiation of higher than 1.6 × 10¹³ n/cm², weakening of the rectification characteristics and recovery of the signal amplitude were observed. These changes imply that deep energy levels, which were also considered to be introduced by defects, were dominant and weakened the effects of the shallow energy levels. Increase in the concentration of the deep trapping levels resulted in gradual decrease of the signal amplitude and degradation in the energy resolution. The peak for the alpha particles was obtained up to 5.5 × 10¹³ n/cm².