Disulfide bond mapping and structural characterization of spruce budworm antifreeze protein

We have previously reported that bryostation 1 (Bryo 1) induces differentiation of chronic lymphocytic leukemia (CLL) in vitro to a hairy cell (HC) stage. This study tests the hypothesis that Bryo 1-differentiated CLL cells are more susceptible to 2-chlorodeoxyadenosine (2-CdA) than parent CLL cells. A recently established EBV-negative CLL line (WSU-CLL) from a patient resistant to chemotherapy including fludarabine was used to test this hypothesis. Both Bryo 1 (10-1000 nM) and 2-CdA (5.6-22.4 microM) exhibited a dose-dependent growth inhibitory effect on the WSU-CLL cell line. In vitro, the sequential exposure to Bryo 1 (100 nM for 72 h) followed by 2-CdA (11.2 microM) resulted in significantly higher rates of growth inhibition than either agent alone. Changes in immunophenotype, enzymes, lipids, proteins, and the DNA of WSU-CLL cells were studied before and after Bryo 1 treatment. Bryo 1 induced a positive tartrate-resistant acid phosphatase reaction and two important markers, CD11c and CD25, after 72 h of culture, confirming the differentiation of CLL to HC. The Fourier transformation infrared spectroscopic analysis showed that the amount of membrane lipids significantly increased in Bryo 1-treated cells compared to controls after 24 h, whereas the protein content, as well as the DNA content, decreased. This finding supports the change of CLL to HC. To evaluate the in vivo efficacy of Bryo 1 and 2-CdA, we used a xenograft model of CLL in WSU-CLL-bearing mice with severe combined immune deficiency. s.c. tumors were developed by injection of 10(7) WSU-CLL cells, and fragments were then transplanted into a new batch of severe combined immunodeficient mice. Bryo 1 and 2-CdA at the maximum tolerated doses (75 micrograms/kg i.p. and 30 mg/kg s.c., respectively) were administered to the mice at different combinations and schedules. The survival in days, the tumor growth inhibition ratio, the tumor growth delay, and the log10 kill of the mice treated with Bryo 1 followed by 2-CdA were significantly better than the control and other groups. We conclude that the sequential treatment with Bryo 1 followed by 2-CdA resulted in higher antitumor activity and improved animal survival.     

Microwave properties of traveling-wave electrodes in LiNbO3 electrooptic modulators

The microwave characteristics of a traveling-wave electrode in electrooptic modulators on z-cut LiNbO₃ crystals with buffer layers with various dielectric constants are calculated by a quasi-TEM analysis. The theoretical results are compared with the measured results on z-cut crystals for coplanar waveguide (CPW) electrodes. The agreement between the calculated and the measured results is good     

A Bayesian approach to subvoxel tissue classification in NMR microscopic images of trabecular bone

NMR microscopy is currently being used as an investigational tool for the evaluation of micromorphometric parameters of trabecular bone as a possible means to assess its strength. Since, typically, the image voxel size is not significantly smaller than individual trabecular elements, partial volume blurring can be a major complication for accurate tissue classification. In this paper, a Bayesian segmentation technique is reported that achieves improved subvoxel tissue classification. Each voxel is subdivided either into eight subvoxels twice the original resolution, or up to four subvoxels along the transaxial direction and the subvoxels optimally classified as volume blurring, the likelihood for the number of marrow subvoxels in each voxel can be computed on the basis of its measured signal. To resolve the ambiguity of the location of the marrow subvoxels, a Gibbs distribution is introduced to model the interaction between the subvoxels. Neighboring subvoxel pairs with the same tissue label are encouraged, and pairs with distinct labels are penalized. The segmentation is achieved by maximizing the a posteriori probability of the label image using the block ICM (iterative conditional mode) algorithm. The potential of the proposed technique is demonstrated in real and synthetic NMR microscopic images.     

Developing a generic FMS for small to medium size industries of Korea

This article reports on the development of a generic FMS that is suitable for small to medium size industries. It introduces FMS construction tool named “shell”, system building methodology using it. Also, it outlines the overview of the developed FMS(KUFMS) and its computer control system. Furthermore, it elaborates on the intercommunication device that links the machinery to its control computer. The factors considered in the development of KUFMS are low implementation cost, easy implementation, case of expandability, simple modification capability.     

Surface spectroscopy and temperature-programmed desorption studies of the interaction of water vapor with Ni3(Al, Ti) (100) and (111) surfaces as a function of temperature

The interaction of water vapor with single crystal Ni₃(Al, Ti) has been studied with Auger electron spectroscopy, photoemission spectroscopy and thermal desorption. Water adsorbs molecularly onto the (111) and (100) surfaces at 140 K. When warmed up to room temperature, water remains as an intact molecule on (111), but dissociates to surface hydroxyl and atomic oxygen on (100). The latter process is accompanied by the evolution of hydrogen and oxidation of Al. It appears that the dissociation of water is structure-sensitive and that Al is the active species in controlling the dissociation of water on Ni₃Al surfaces.     

Cytotoxic potential of monoalkylation products between mitomycins and DNA: studies of decarbamoyl mitomycin C in wild-type and repair-deficient cell lines

Hypoxic regions in solid neoplasms have been associated with tumor recurrence and resistance to several cancer treatment modalities including radiation therapy. Various strategies have been designed to target these resistant cells, including the use of the bioreductive alkylating agent mitomycin C (MC), which exerts preferential cytotoxicity under hypoxic conditions in most cell lines. Analyses of the mechanism of action of MC indicate that this drug can form cross-links with DNA; it is currently thought that this bisadduct is the critical lesion responsible for inhibiting DNA synthesis. Computer-generated models suggest that the MC adduct fits snugly into the minor groove of B-DNA without imposing major distortion on the structure of the DNA molecule. To gain additional insight into the role of cross-linkage in the cytotoxicity of MC, we studied the analogue, decarbamoyl mitomycin C (DMC). The structure of DMC is identical to that of MC with the exception of the substitution of the carbamoyl group at the C-10 position by a nonalkylating hydroxyl group (-OH); this alteration would be expected to prevent DMC from forming bisadducts with DNA. In chemical systems, DMC produces only DNA monoadducts. If indeed it is the MC-DNA cross-links which are responsible for cell kill, one would predict DMC to be less cytotoxic than MC. However, tissue culture studies using DMC revealed that DMC is at least as toxic as MC to EMT6 mouse mammary tumor cells and to wild-type AA8 Chinese hamster ovary (CHO) cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)