Long-term development of the radionuclide exposure of murine rodent populations in Belarus after the Chernobyl accident.

As a determinant of the associated health risks, the behavior of radionuclides in natural ecosystems needs to be better understood. Therefore, the activity concentration of various long-lived radionuclides released due to the Chernobyl accident, and the corresponding contributions to the whole-body dose rate, was studied as a function of time in mammalian indicator species inhabiting the natural forest ecosystems of Belarus, the bank vole (Clethrionomys glareolus) and the yellow-necked mouse (Apodemus flavicollus). The activity concentrations of 137Cs, 134Cs, 90Sr, 238Pu, 239,240Pu, 241Pu and 241Am in soil and in animals were measured at five monitoring sites with different ground deposition of radionuclides at different distances from the destroyed reactor. The observed temporal pattern of the radionuclide activity concentration in the studied animal populations reflects the changes in biological availability of these isotopes for biota, mostly due to fuel particle destruction and appearance of dissolved and exchangeable forms of radionuclides. The time course of 134+137Cs activity concentrations in animal populations appeared as a sequence of increase, peak and decrease. Maximal levels of radiocesium occurred 1-2 years after deposition, followed by an exponential decrease. Concentrations of incorporated 90Sr increased up to the tenth year after deposition. The activity concentrations of transuranic elements (238Pu, 239,240Pu, 241Pu and 241Am) were much lower than those of the other radionuclides, in the studied animals. A considerable activity of 241Am in animals from areas with high levels of contamination was firstly detected 5 years after deposition, it increased up to the tenth year and is expected to increase further in the future. Maximal values of the whole-body absorbed dose rates occurred during the year of deposition, followed by a decrease in the subsequent period. Generally, this decrease was monotonic, mainly determined by the decrease of the external gamma-ray dose rate, but there were exceptions due to the delayed maximum of internal exposure. The inter-individual distributions of radionuclide concentrations and lifetime whole-body absorbed doses were asymmetric and close to log-normal, including concentrations and doses considerably higher than the population mean values.

FT-IR study of a chemically amplified resist for X-ray lithography.

Microelectronic devices for future applications demand lithographic performance that falls within the 0.10 microm region and below. Chemically amplified resists (CARs), such as the positive tone commercial UVIII resist, offer a substantial gain in sensitivity, resolution, and process efficiency in deep ultraviolet, e-beam, and X-ray lithographies. In this work, the UVIII resist is characterized for X-ray lithographic applications by studying the "deprotection" or acid generation-diffusion process of the resist under different conditions of post-exposure bake (PEB) temperature and time, and of X-ray exposure dose. The X-ray irradiation from a copper anode at a wavelength of 1.33 nm was at an intensity of 30 microW/cm2 on the resist surface. The deprotection process of the resist during PEB was accurately monitored by using Fourier transform infrared (FT-IR) spectroscopy. The infrared absorption peaks at 1151, 1369, and 2977 cm(-1) in the spectrum of the UVIII resist were found to be useful indicators for the completion of deprotection. Results of the experiments showed that the performance of UVIII could be optimized at the PEB temperature of 140 degrees C, a time of 2 min, and X-ray exposure dose of 12 mJ/cm2. The change in resist thickness after PEB was also measured. The results were confirmed by scanning electron microscopy (SEM) in which a test structure as small as 0.12 microm was obtained in a 1-microm-thick UVIII resist layer.

Simple reflow technique for fabrication of a microlens array in solgel glass.

A simple reflow method for fabrication of refractive microlens arrays in inorganic-organic SiO2-ZrO2 solgel glass is presented. To our knowledge, this is the first report that presents a simple reflow technique for transforming a negatively induced hybrid solgel material into desirable spherical microlenses. It is shown that the microlenses have excellent smooth surfaces and uniform dimensions. The reflow technique is considerably cheaper than use of a high-energy beam-sensitive gray-scale mask and is suitable for mass production.

Optimized polarization-selective computer-generated hologram with fewer phase combinations.

Normally, to incorporate two binary conventional computer-generated holograms (CGHs) into a single polarization-selective computer-generated hologram (PSCGH), the respective pixels of the conventional CGHs will result in 4 different combinations of the phase values. Thus, the 4 phase combinations have to be realized by 4 types of pixel structures in a PSCGH. In this paper, we propose a method to reduce the PSCGH's 4 phase combinations to 3 using an optimization approach. The PSCGH's first-order diffraction efficiency is 30% and the contrast ratio is 28 after the optimization.

Toward optimized carbohydrate-based anticancer vaccines: epitope clustering, carrier structure, and adjuvant all influence antibody responses to Lewis(y) conjugates in mice.

The feasibility of using carbohydrate-based vaccines for the immunotherapy of cancer is being actively explored at the present time. Although a number of clinical trials have already been conducted with glycoconjugate vaccines, the optimal design and composition of the vaccines has yet to be determined. Among the candidate antigens being examined is Lewis(y) (Le(y)), a blood group-related antigen that is overexpressed on the majority of human carcinomas. Using Le(y) as a model for specificity, we have examined the role of epitope clustering, carrier structure, and adjuvant on the immunogenicity of Le(y) conjugates in mice. A glycolipopeptide containing a cluster of three contiguous Le(y)-serine epitopes and the Pam(3)Cys immunostimulating moiety was found to be superior to a similar construct containing only one Le(y)-serine epitope in eliciting antitumor cell antibodies. Because only IgM antibodies were produced by this vaccine, the effect on immunogenicity of coupling the glycopeptide to keyhole limpet hemocyanin was examined; although both IgM and IgG antibodies were formed, the antibodies reacted only with the immunizing structure. Reexamination of the clustered Le(y)-serine Pam(3)Cys conjugate with the adjuvant QS-21 resulted in the identification of both IgG and IgM antibodies reacting with tumor cells, thus demonstrating the feasibility of an entirely synthetic carbohydrate-based anticancer vaccine in an animal model.

Immunization of ovarian cancer patients with a synthetic Lewis(y)-protein conjugate vaccine: a phase 1 trial.

As the initial step in developing carbohydrate-based vaccines for the treatment of ovarian cancer patients in an adjuvant setting, 25 patients were immunized with a Lewis(y) pentasaccharide (Le(y))-keyhole limpet hemocyanin (KLH)-conjugate vaccine together with the immunological adjuvant QS-21. Four different doses of the vaccine, containing 3, 10, 30, and 60 microg of carbohydrate were administered s.c. at 0, 1, 2, 3, 7, and 19 weeks to groups of 6 patients. Sera taken from the patients at regular intervals were assayed by ELISA for reactivity with naturally occurring forms of Le(y) (Le(y)-ceramide and Le(y) mucin) and by flow cytometry and a complement-dependent cytoxicity assay for reactivity with Le(y)-expressing tumor cells. The majority of the patients (16/24) produced anti-Le(y) antibodies as assessed by ELISA, and a proportion of these had strong anti-tumor cell reactivity as assessed by flow cytometry and complement-dependent cytotoxicity. One serum, analyzed in detail, was shown to react with glycolipids but not with glycoproteins or mucins expressed by ovarian cancer cell line OVCAR-3. The vaccine was well tolerated and no gastrointestinal, hematologic, renal, or hepatic toxicity related to the vaccine was observed. On the basis of this study, Le(y)-KLH should be a suitable component for a polyvalent vaccine under consideration for the therapy of epithelial cancers.

Polyclonal antibodies from patients immunized with a globo H-keyhole limpet hemocyanin vaccine: isolation, quantification, and characterization of immune responses by using totally synthetic immobilized tumor antigens.

We have previously reported on a carbohydrate-based vaccine program for immunotherapy in cancer patients. One such vaccine, based on the globo H antigen conjugated to the protein keyhole limpet hemocyanin (KLH), has been in clinical evaluation. Although this and other carbohydrate vaccines have been shown to induce antibody responses, there are currently no quantitative data on the antibody levels achieved in immunized patients by these or other anti-cancer vaccines. We report herein an efficient route to complex synthetic oligosaccharides attached to an affinity matrix for identifying and isolating antibodies elicited against such a carbohydrate-based vaccine in humans. Pre- and postvaccination profiles from serum samples of patients immunized with globo H-KLH were compared. All anti-globo H antibody activity was efficiently separated from other serum constituents. The isolated antibodies were readily quantified, and their specificities were analyzed. Since no comparable data were available on antibodies resulting from the vaccination of other cancer patients, we compared the observed levels with those quoted in studies with bacterial polysaccharide vaccines that had been quantified. Remarkably, cancer patients immunized with globo H-KLH produce anti-globo H antibody levels often exceeding those formed by immunization with bacterial polysaccharides. In addition, substantial quantities of both IgG and IgM antibodies were elicited, clearly indicating a class switch to IgG. Taken together, these analyses serve to clarify several aspects of the immune response to the vaccine and give several new insights to the carbohydrate-based vaccination strategy. Furthermore, antibodies so isolated could well have applications in clinical therapy.

Selection of carbohydrate antigens in human epithelial ovarian cancers as targets for immunotherapy: serous and mucinous tumors exhibit distinctive patterns of expression.

Expression of blood group-related carbohydrate antigens was examined in frozen sections from a series of ovarian carcinomas of different histological types using an indirect immunoperoxidase technique. Antigenic specificities belonging to the O(H) and Lewis blood group families (H-1, H-2, Le(a), sLe(a), Le(x), sLe(x), Le(b) and Le(y)) or the mucin-core family (Tn, sTn and TF) were studied. A distinct difference in antigen expression between mucinous and other ovarian carcinomas (serous and endometrioid) was observed. Specifically, mucinous tumors tended to express sTn, Le(a) and sLe(a) strongly and homogeneously, whereas serous and endometrioid tumors rarely expressed these specificities and, in contrast, expressed Le(y) and H type 2 antigen strongly. When expressed in serous tumors, sTn was usually distributed in a heterogeneous pattern, whereas sTn expression in mucinous tumors was much more homogeneous. The distribution of Le(y) in serous tumors was noticeably homogeneous. H-1, Le(x), sLe(x), Le(b), TF and Tn specificities were rarely expressed in any type of ovarian carcinoma. Our results provide further support for the different histogenesis of mucinous and non-mucinous tumors and indicate alternative differentiation pathways for the 3 pathological subtypes of ovarian tumor. They also provide the basis for the choice of carbohydrate antigens for active and passive immunotherapy of ovarian carcinomas.

Characterization of a mouse monoclonal IgG3 antibody to the tumor-associated globo H structure produced by immunization with a synthetic glycoconjugate.

Globo H (Fuc alpha1 --> 2Galbeta1 --> 3GalNAcbeta1 --> 3Gal alpha1 --> 4Galbeta1 --> 4Glc) is a carbohydrate structure that shows enhanced expression in many human carcinomas. From mice immunized with a globo H-KLH (keyhole limpet hemocyanin) synthetic conjugate an IgG3 monoclonal antibody (mAb VK-9) was derived that recognizes the globo H structure. Serological analysis showed that the minimal structure recognized by this mAb was the tetrasaccharide sequence Fuc alpha1 --> 2Galbeta1 --> 3GalNAcbeta1 --> 3Gal. An isomeric structure with an internal alphaGalNAc linkage was also recognized but less efficiently. mAb VK-9 did not react with many related structures, such as galactosylgloboside, globoside, H type 1, H type 2 blood group structures or fucosyl-gangliotetraosyl ceramide, but did react weakly with globo A ceramide. Not only did mAb VK-9 react with carbohydrate-protein conjugates but it could also recognize globo H-ceramide and human tumor cells expressing globo H. These results suggest that globo H-KLH could be explored as a vaccine in the treatment of carcinoma patients.

Immunogenicity of synthetic conjugates of Lewis(y) oligosaccharide with proteins in mice: towards the design of anticancer vaccines.

Many human carcinomas overexpress the Lewis(y) (Le[y]) blood-group epitope [Fucalpha1-->2Galbeta1-->4 (Fucalpha1-->3)GlcNAcbeta1-->3Gal-]. With a view to developing Le(y) based vaccines we have examined the immunogenicity of Le(y)-protein conjugates in mice. Le(y) pentasaccharide was synthesized as its allyl glycoside and coupled to keyhole limpet hemocyanin (KLH) by reductive amination or by a novel method utilizing a maleido-derivitized alkyl carboxyhydrazide as a bridging group to 2-iminothiolane-derivitized KLH. Le(y) oligosaccharide was also coupled to bovine serum albumin by reductive amination. Immunization of groups of mice with the three conjugates, together with the immunological adjuvant QS21, showed that Le(y) oligosaccharide directly coupled to KLH was the most efficient conjugate for eliciting IgG and IgM antibody responses to naturally occurring forms of Le(y) epitopes carried on mucins and glycolipids. These antibodies were also reactive with and cytotoxic to a human breast cancer cell line expressing Le(y) (MCF-7). These experiments suggest that Le(y)-KLH antigen and QS21 adjuvant could be considered as an immunogenic therapeutic vaccine in carcinoma patients.

Analysis of the carbohydrate specificity of ISOBM TD-4 Workshop anti-MUC1 antibodies.

The panel of ISOBM TD-4 Workshop antibodies was tested against a range of carbohydrate antigens consisting of (a) ovarian cyst mucins expressing A, B, H, Le(a), Le(x), Le(b), Le(y) and precursor (nonfucosylated) specificities, (b) ovine submaxillary mucin (OSM, expressing sialyl Tn) and desialylated OSM (expressing Tn) and (c) synthetic glycoconjugates (Le(a)-PAA and Le(x)-PAA). The assay used was an ELISA method using rabbit anti-mouse Ig as the second reagent. Thirty-five of the 51 antibodies were unreactive with this group of antigens and presumably react with MUC1 peptide or a carbohydrate specificity not represented. Two MAbs (127 and 128) detected Le(x) antigen and one MAb (157) reacted with A blood group. MAb 151 (and possibly 152) detected sialyl Tn epitopes. Three antibodies (139, 149 and 168) reacted with nonfucosylated structures (possibly LNT or LNneoT). A number of MAbs (137, 145, 162, 163 and 164) reacted widely with the panel of antigens; whether these are nonspecific reactions due to 'sticky' antibodies or caused by the presence of MUC1 peptide in the antigen preparations is uncertain.

Isolation and characterization of ovarian cancer antigen CA 125 using a new monoclonal antibody (VK-8): identification as a mucin-type molecule.

A new murine monoclonal antibody (MAb VK-8), detecting the CA 125 ovarian cancer antigen, was used to purify this antigen from OVCAR-3 ovarian cancer cells by affinity chromatography. The biochemical properties of the purified antigen are characteristic of a mucin-type glycoprotein: (1) the molecule is highly glycosylated (77% w/w), mainly with galactose, N-acetylglucosamine, and N-acetylgalactosamine, (2) the protein moiety is rich in serine, threonine and proline, (3) many of the serine and threonine residues are glycosylated, (4) the glycan chains are almost entirely O-linked, with core 2 [Galbeta1 --> 3(GlcNAcbeta1 --> 6)GalNAc] structures predominating and (5) these chains carry fucosylated Type 2 (Le(y) and Le(x) and H type 2) blood group structures. The antigen exhibited a very high m.w. (> 10(3) kDa) in aqueous buffer as well as in urea, but was degraded by proteolytic enzymes to smaller fragments that no longer reacted with the antibody. Although this result, and other immunochemical data, indicate that OC125, the original MAb to CA125, and VK-8 antibodies detect epitopes on the protein portion of the molecule, the involvement of carbohydrate cannot be ruled out. Further insight into the structure and function of the CA125 antigen will come from cloning the gene coding for the peptide backbone, and from more detailed carbohydrate structural analysis.

Comparison of O-linked carbohydrate chains in MUC-1 mucin from normal breast epithelial cell lines and breast carcinoma cell lines. Demonstration of simpler and fewer glycan chains in tumor cells.

MUC-1 mucin is considered to be aberrantly glycosylated in breast, ovary, and other carcinomas in comparison with mucin from corresponding normal tissues. In order to clarify these differences in glycosylation, we have compared the O-linked carbohydrate chains from MUC-1 immunoprecipitated from [3H]GlcN-labeled breast epithelial cell lines (MMSV1-1, MTSV1-7, and HB-2) derived from cells cultured from human milk, with three breast cancer cell lines (MCF-7, BT-20, and T47D). Analysis by high pH anion chromatography showed that the normal cell lines had a higher ratio of GlcN/GalN and more complex oligosaccharide profiles than the cancer cell lines. Structural analyses were carried out on the oligosaccharides from MTSV1-7 and T47D MUC-1, and the following structures were proposed. MUC-1 from T47D had rather a simple glycosylation pattern, with NeuAcalpha2-3Galbeta1-3GalNAc-ol, Galbeta1-3GalNAc-ol, and GalNAc-ol predominating; in contrast, MUC-1 from MTSV1-7 had more complex structures, including a number of disialo, core 2 species, i.e. NeuAcalpha2-3Galbeta1-4GlcNAcbeta1-6[NeuAcalpha2 -3Galbeta1-3]GalNAc- ol and NeuAcalpha2-3Galbeta1-4GlcNAcbeta1-6[NeuAcalpha2 -3Galbeta1-4GlcNAcbet a1-3Galbeta1-3]GalNAc-ol. Double-labeling experiments with [3H]GlcN and 14C-aminoacids and analysis of GalNAc or GalNAc-ol:protein ratios in MUC-1 showed that there was also a significant difference in the degree of glycosylation of the mucin between the two cell types. We conclude that MUC-1 from breast cancer cell lines has simpler, and fewer, carbohydrate chains than MUC-1 from normal breast epithelial cells, and that these differences, combined or separately, explain the differential tumor specificity of some MUC-1 antibodies and T cells.

Serological and immunochemical analysis of Lewis y (Ley) blood group antigen expression in epithelial ovarian cancer.

The expression of Ley blood group antigen in epithelial ovarian cancer tissues and cell lines has been studied using a Ley-specific monoclonal antibody (MAb 3S193). In ovarian cancer specimens, Ley was expressed in 75% of the 140 tumor specimens examined, with strong or moderate expression being observed in 56% of the samples. Seven of the 11 ovarian cancer cell lines studied were Ley-positive. Using immunochemical approaches, Ley epitopes were found to be expressed on 4 types of carrier molecules: CA125 ovarian cancer antigen, MUC-1 mucins, lower m.w. glycoproteins and glycolipids. In cell lines, Ley was more commonly expressed on MUC-1 mucin than on CA125, whereas in tumor specimens Ley was commonly found on both CA125 and MUC-1. The biochemical nature of the smaller Ley glycoproteins was not determined, but it was shown that they were not CEA and LAMP-1, known Ley carriers in some other tumor types. Glycolipids carrying Ley epitopes were detected in both ovarian cancer cell lines and tumor specimens. The presence of Ley epitopes on a number of different molecular carriers, including 2 major ovarian cancer antigens (CA125 and MUC-1), explains the high incidence of Ley in ovarian cancer. The high expression of Ley in ovarian cancer and the availability of specific murine and humanized MAbs make Ley an attractive candidate target for clinical studies.

Estudio de aerosoles y cenizas dispersados durante la erupción del volcán Popocatétl del 21 de diciembre de 1994.- Resultados preliminares

La erupción de baja energía térmica del 21 de diciembre de 1994 del volcán Popocatépetl brindó una oportunidad única para llevar a cabo varias investigaciones para determinar es espectro total de tamaños de cenizas y aerosoles volcánicos, su composición elemental, microestructura, y finalmente, análisis de dispersión. Se efecturaon mediciones en superficie y por medio de avión utilizando : Un contador fotoeléctrico de particulas (d> 0.4 um a d < 50 um), la concentración y dispersividad para d > 0.01 um a d < 20 um se midieron con un impactor de dos cascadas, las muestras se sujetaron a análisis de microscopía electrónica y de óptica para detectar partículas d = 500 um. Se usaron filtros de Petryanov para determinación posterior de la composición de elementos químicos por medio de activación de deutrones, fluorescencia de rayos-X y espectroscopia de absorción atómica (AU)