Anticancer efficacy in vivo and in vitro, synergy with 5-fluorouracil, and safety of recombinant methioninase

The elevated exogenous-methionine dependency of tumors for growth has been observed in all major cancer cell types. We have previously cloned a methioninase (rMETase) from Pseudomonas putida to deplete methionine. Growth inhibition followed by apoptotic cell death was induced by treatment of tumor cells with rMETase in vitro. A single i.p. injection of 300 units of rMETase can lower the serum methionine level in the mice from 70 microM to less than 1 microM within 2 h and maintain this depleted level for 8 h. Repeated dosing of rMETase of tumor-bearing mice could be administered without acute immune-hypersensitivity. rMETase treatment demonstrated growth inhibitory activity against human tumors in nude mice, including those which were multiple drug-resistant. No body weight loss or hematotoxicity, except a slight anemia, was found throughout the therapy. The combined treatment of the Lewis lung carcinoma with a fixed rMETase dose and increasing doses of 5-fluorouracil (5-FU) resulted in a dose-dependent enhanced antitumor efficacy for survival as well as tumor growth inhibition. Thus, methionine depletion by rMETase potentiates the antitumor efficacy of 5-FU. The data presented in this report thus indicate that rMETase is active alone, is synergistic in combination with 5-FU, and has negligible toxicity suggesting a novel clinical approach for effective cancer therapy.     

Shortening of the intraventricular conduction time in premature ventricular beats during ventricular extrastimulation: possible role of dimensional shortening of the conducting distance during ventricular systole

INTRODUCTION: Conduction time (CT) is given by the formula: conducting distance divided by conduction velocity. Based on this formula, we hypothesized that CT shortening (i.e., supernormal conduction) may result from dimensional shortening of the distance of impulse propagation, which naturally occurs during ventricular systole. METHODS AND RESULTS: To test the above, two separate groups of patients were studied, group A (14 patients) for electrophysiologic study and group B (12 patients) for echocardiographic study. In group A patients, CT from the stimulus artifact to the basal lateral wall of the left ventricle (LV) (S-LV interval) was measured using right ventricular (RV) apical extrastimulus testing. S-LV interval shortening in premature RV beats was demonstrated in all 14 patients. The maximum shortening was 20 +/- 9 msec (range 10 to 40), and the maximum % shortening was 16% +/- 6% (7% to 27%). In group B patients with implanted pacemakers, the major (long) and minor (short) axis dimensions of the LV were measured with echocardiography. The major axis dimension was used as an approximate measure of the linear length from the RV apex to the basal lateral wall of LV. The maximum % shortening of the major axis dimensions was 15% +/- 4%, 16% +/- 2%, and 11% +/- 4% during VVI pacing, respectively, at paced cycle lengths of 1,000 (11 patients), 800 (5 patients), and 600 msec (12 patients). The maximum % shortening of the S-LV intervals was comparable in magnitude with that of the major axis dimensions: 20% versus 15% +/- 4%, 15% +/- 7% versus 16% +/- 2% and 16% +/- 6% versus 11% +/- 4%, respectively, at paced cycle lengths of 1,000, 800, and 600 msec. There was also a good temporal correlation between the electrophysiologic (CT shortening) versus echocardiographic (dimensional shortening) parameters. Thus, the intraventricular CT and the major axis dimension of the LV were shortened in a similar magnitude and also at a similar timing in the cardiac cycle. CONCLUSION: These findings suggest the possibility that supernormal conduction may result, at least in part, from dimensional shortening of the pathway length of impulse propagation from the stimulating to recording electrodes, which naturally occurs during ventricular systole.     

Expression of erythroid-specific genes in acute megakaryoblastic leukaemia and transient myeloproliferative disorder in Down's syndrome

Acute megakaryoblastic leukaemia (M7) and transient myeloproliferative disorder in Down's syndrome (TMD) are characterized by rapid growth of abnormal blast cells which express megakaryocytic markers. To clarify properties of the blast cells in M7 and TMD cases, we examined erythroid markers expression in blasts from six cases with M7 and seven cases with TMD in this study. Erythroid-specific mRNAs encoding gamma-globin and erythroid delta-aminolevulinate synthase were found to be expressed in blasts from most of these cases, indicating that majorities of the blasts in M7 and TMD cases have erythroid and megakaryocytic phenotypes. We also found that mRNAs encoding GATA-1 and GATA-2 are expressed in all these cases. These results suggest that M7 blasts and TMD blasts correspond to the erythroid/megakaryocytic bipotential progenitor cells.     

A new assessment of quality of life (QOL) for cancer patients

A new assessment of quality of life (QOL) was made for cancer patients. The QOL assessment consists of 12 items: pain; nausea; constipation; general fatigue; sleep; eating; activity; a daily life pattern; conversation; treatment acceptability; satisfaction at the present status and family exhaustion. Ranges of scores are one (best) to five (worst). For visual expression of QOL, the author made an original method called "QOL diagram", drawn with a circle which has 12 diverging lines marked five points indicating the score for each item. QOL changes after cancer pain control with either oral or intravenous morphine were examined in 22 adult cancer patients by the QOL assessment. Laxatives and anti-nausea drugs were mostly prescribed at the same time in order to avoid side effects of morphine. QOL was evaluated and recorded by the author through an individual interview with each patient. It was observed that the psychological factors were improved along with pain relief. Although items such as general fatigue, nausea, constipation, sleep and eating did not change considerably at first, they improved well with time in the oral morphine group. On the other hand, there was no marked time-dependent change in the intravenous morphine group. Items such as activity, a daily life pattern and conversation were rather negative than positive. These items seem to be more important to improve QOL of the cancer patients, in particular, whose general status is relatively good. In conclusion, the QOL diagram helped us to follow subtle changes of status and needs of cancer patients. And it enables us to easily assess risks and benefits of the treatment plans including palliative care and home supportive programs. It is designed for both patients and medical staffs to use easily and repeatedly. However, the further evaluation and refinement will be needed to verify validity and reliability of the QOL diagram before a routine clinical application.     

Post-priming actions of ATP on Ca2+-dependent exocytosis in pancreatic beta cells

The role of cytosolic ATP in exocytosis was investigated by using amperometric measurement of insulin exocytosis in pancreatic beta cells, which were stimulated with photolysis of caged Ca2+ compounds. Insulin exocytosis occurred with two rates. We found that ATP hastened and augmented the exocytosis via selective enhancement of the exocytosis with the faster rate. A nonhydrolysable analog of ATP, adenosine 5'-O-(3-thiotriphosphate), which blocks ATPase, was even more effective than ATP, indicating that the phosphorylation event occurred downstream of ATP-dependent vesicle transportation and priming. The action of ATP was eliminated by a competitive antagonist of cAMP, and by an inhibitor of adenylate cyclase. These data characterize an ATP sensing mechanism for the Ca2+-dependent exocytosis involving adenylate-cyclase, cAMP-dependent protein kinase, and, possibly, the fusion machinery itself. Thus, the fast exocytotic machinery requires both phosphorylation and Ca2+ for the final triggering and likely constitutes a distal ATP sensor for insulin exocytosis that acts in concert with ATP-sensitive K+ channels.     

Study on the Effect of Elastic Stress and Microstructure of Low Carbon Steels on Barkhausen Noise

The present study investigates the effect of elastic stress and microstructure on Barkhausen noise in low carbon steels subjected to different heat treatments. Barkhausen noise in an as-received test piece and a test piece heated at 450 ^°C for 1.5 hours was found to increase with increasing elastic stress. However, in a test piece heated at 700 ^°C for 10 hours, Barkhausen noise was observed to saturate with increasing elastic stress following an initial increase. To clarify the reason for this saturation behavior, magnetization measurements were carried out and the microstructure and texture of the test pieces were evaluated using microscopy and electron backscatter diffraction. The results indicated that for the test piece heated at 700 ^°C for 10 hours, a drastic change in the microstructure occurred compared to that for the other test pieces. From the experimental and analytical results, it was concluded that for the former test piece, Barkhausen noise saturated under a low elastic stress due to the globularization of pearlite, which caused 90^° domain walls to become 180^° domain walls when a low elastic stress is applied.     

Algorithms for computing the maximum weight region decomposable into elementary shapes

Motivated by the image segmentation problem, we consider the following geometric optimization problem: Given a weighted n × n pixel grid, find the maximum weight region whose shape is decomposable into a set of disjoint elementary shapes. We give efficient algorithms for several interesting shapes. This is in strong contrast to finding the maximum weight region that is the union of elementary shapes for the corresponding cases—a problem that we prove to be NP-hard. We implemented one of the algorithms and demonstrate its applicability for image segmentation.     

Development of an Eddy Current Inspection Technique with Surface Magnetization to Evaluate the Carburization Thickness of Ethylene Pyrolysis Furnace Tubes

An eddy current inspection system that incorporates a C-core probe and a direct current magnetizer for HP-grade ethylene pyrolysis tubes was developed to estimate the degree of carburization of the tubes. Through the development process, the characteristics of the B?CH curves and the electric conductivities of service-aged tubes were clarified, and a method of counteracting the external magnetism of the tube, which disturbs the accurate detection of the degree of tube carburization, by installing a direct current magnetizer was validated. The influence of tube external magnetism in the oxide/nitride layer was properly canceled by installing a magnetizer with a magnetizing current of 0.5?A on the external surface of the tube. In addition, a calibration curve correlating the carburization depth from the external surface of the tube with the normalized inductance was obtained by finite element analysis simulation. The calibration curve revealed that the degree of carburization could be quantitatively evaluated from the detected normalized inductance of service-aged tubes using the developed inspection system.     

Boron-dependent regulation of translation through AUGUAA sequence in yeast

Under high boron (B) conditions, nodulin 26-like intrinsic protein 5;1 (NIP5;1) mRNA, a boric acid channel, is destabilized to avoid excess B entry into roots of Arabidopsis thaliana. In this regulation, the minimum upstream open reading frame (uORF), AUGUAA, in its 5′-untranslated region (5′-UTR) is essential, and high B enhances ribosome stalling at AUGUAA and leads to suppression of translation and mRNA degradation. This B-dependent AUGUAA-mediated regulation occurs also in animal transient expression and reticulocyte lysate translation systems. Thus, uncovering the ubiquitousness of B-dependent unique regulation is important to reveal the evolution of translational regulation. In the present study, we examined the regulation in Saccharomyces cerevisiae. Reporter assay showed that in yeast, carrying ATGTAA in 5′-UTR of NIP5;1 upstream of the reporter gene, the relative reporter activities were reduced significantly under high B conditions compared with control, whereas deletion of ATGTAA abolished such responses. This suggests that AUGUAA mediates B-dependent regulation of translation in Saccharomyces cerevisiae. Moreover, the deletion of ATGTAA resulted in up to 10-fold increase in general reporter activities indicating the suppression effect of AUGUAA on translation of the main ORF. Interestingly, mRNA level of the reporter gene was not affected by B in both yeast cells with and without AUGUAA. This finding reveals that in yeast, unlike the case in plants, mRNA degradation is not associated with AUGUAA regulation. Together, results suggest that B-dependent AUGUAA-mediated translational regulation is common among eukaryotes.     

Dynamics and control of recombination process at semiconductor surfaces, interfaces and nano-structures

Characterization methods and fundamental aspects of surface/interface states and recombination process in Si and III–V materials are reviewed. Various measurement considerations are pointed out for the conventional metal–insulator–semiconductor (MIS) capacitance–voltage (C–V) method, a contactless C–V method, and the microscopic scanning tunneling spectroscopy (STS) method, and general features of surface states are discussed. Surface states are shown to have U-shaped distributions of donor–acceptor continuum with a characteristic charge neutrality level, E_HO. Rigorous simulation of dynamics of surface recombination process has shown that the effective surface recombination velocity, S_eff, is not a constant of the surface, but its value changes by many orders of magnitude with the incident light intensity and the polarity and amount of fixed charge. From this, new methods of surface state characterization based on photoluminescence and cathodoluminescence are derived. Attempts to control surface states and Fermi level pinning at metal semiconductor interface and free surfaces of nano-structures are presented as efforts toward “nano-photovoltaics”.