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A theoretical analysis of the angular resolution of two-dimensional interferometric radiometers for Earth observation from low-orbit satellites and its degradation due to spatial decorrelation effects is presented. The analysis extends basic effects known in the context of radio astronomy (application with narrow field of view, very few baselines) and in one dimension (ESTAR L band, few baselines interferometric radiometer) to the wide-field-of-view, many-baseline, high-resolution two-dimensional system required by Earth observation applications and computes beam width, encircled energy (or main beam efficiency), and side lobe level as a function of windowing (apodization) to allow for an optimum angular versus radiometric resolution trade-off. It is found that the extension of the Barlett window (which has a poor performance in one dimensional signal processing) to two dimensions produces high-quality results, comparable or better than those of Gaussian and Blackmann windows. Theory is extended to hexagonally sampled systems based on a ¿ or Y-shaped instrument, with hexagonal- and star-shaped support regions in the visibility space, respectively. The superior performance of the latter over the former for the same number of antennas and correlators is quantified and details of the angular resolution of one instrument of this kind, MIRAS, under development by the European Space Agency, are presented. For this radiometer Gaussian or Barlett windows should be used for good radiometric sensitivity or spatial resolution, respectively. In both cases the effects of decorrelation within the small alias-free field of view are negligible. It is also found that the impact of hardware imperfections which exist within the strict requirements of the specifications have a negligible effect on the angular resolution. Finally, experimental angular resolution results with a laboratory breadboard in a focused near-field setup are presented and compared to the theoretical predictions.

In the last years aperture synthesis interferometric radiometers have received a special attention by space agencies as a feasible solution to passive monitoring of the Earth at low frequencies (L-band), where classical total power radiometers would require heavy steerable antennas to meet the spatial resolution requirements (10 - 20 Km), from a low polar orbit. While the performance of such instruments is well known in the radioastronomy field, its application to Earth remote sensing is quite new. The study of different array structures, system errors, calibration and inversion methods and instrument global performance requires the implementation of a simulator of a two-dimensional space borne interferometric radiometer. It allows us to analyze not only its snap shot radiometric accuracy, but also its improvement by means of pixel averaging, that is, the averaging of the common pixels recovered in a sequence of consecutive brightness temperature images. The simulations performed use the system parameters of the planned MIRAS (microwave imaging radiometer by aperture synthesis) instrument, a Y-shaped array with 43 antennas per arm spaced 0.89 lambda, currently under study by the European Space Agency.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Summary Eighty-eight monoclonal antibodies were tested by immunohistochemistry on human gastro-duodenal mucosae of known ABO, Lewis and Secretor phenotypes. Antibodies were classified among anti-A, anti-B, anti-AB, anti-H and other anti-glycoconjugates (I, i, T, Tn, Lewis, P1, Tk). Anti-A, B and AB antibodies were subdivided into subgroups with “broad” or “restricted” reactivity according to the extent of epithelial cell labeling. Anti-H antibodies were classified in accordance to their degree of sensitivity to the secretor phenotype. Among anti-T and anti-I antibodies, only one of each showed positive staining of epithelial cells. All anti-Lewis antibodies had distinct reactivites, although, they were clearly anti-Lewis reagents. Some anti-P1 antibodies labeled epithelial cells, irrespective of the ABO, Lewis and secretor phenotypes. One anti-Tk stained the Golgi apparatus of most epithelial cells, irrespective of the individual's phenotype. In conclusion, some of the antibodies tested were defined as very useful reagents for immunohistochemistry showing both specificity and sensitivity.

Devazepide (L-364718, a non-peptide antagonist of CCK-A receptors), inhibits the proliferation and induces morphologic changes in the mucous-secreting, autonomously proliferating human cancer colon cell line (HT29-S-B6. Addition of devazepide (10 microM) for at least 3 days in the exponential phase of growth enhanced the baseline production of gastric M1 mucins 2-3-fold and that of carcinoembryonic antigens 5-fold. Moreover, devazepide induced an increase in the amount of the MUC-5AC mRNA expressed by HT29-S-B6 cells. The increased in mucins secretion induced by devazepide was persistent after removal and independent of the presence of serum. In conclusion, devazepide-L-364718 behaves as a maturation agent in the cell clone HT29-S-B6.

When a large aperture is used to collect light propagated through the atmosphere, it performs an average operation on the irradiance fluctuations, resulting in collected-power fluctuations that are not as large as those that could be obtained from a point receiver. We present an expression for the aperture-averaging factor of optical scintillation using multiaperture architectures on the receiver configuration. That expression is used to assess the decrease in the total collected power fluctuations for several multiaperture receiver configurations. © 1996 Society of Photo-Optical Instrumentation Engineers.

Using immunochemical and immunohistochemical methods, the binding site of Anguilla anguilla agglutinin (AAA) was characterized and compared with the related fucose-specific lectin from Ulex europaeus (UEA-I). In solid-phase enzyme-linked immunoassays, the two lectins recognized Fuc alpha 1-2Gal beta-HSA. AAA additionally cross-reacted with neoglycolipids bearing lacto-N-fucopentaose (LNFP) I [H type 1] and II [Le(a)] and lactodifucotetraose (LDFT) as glycan moieties. UEA-I, on the other hand, bound to a LDFT-derived neoglycolipid but not to the other neoglycolipids tested. Binding of AAA to gastric mucin was competitively neutralized by Le(a)-specific monoclonal antibodies. UEA-I binding, on the other hand, was reduced after co-incubation with H type 2- and Le(y)-specific monoclonal antibodies. According to our results, AAA reacts with fucosylated type 1 chain antigens, whereas UEA-I binds only to the alpha 1-2-fucosylated LDFT-derived neoglycolipid. In immunohistochemical studies, the reactivity of AAA and UEA-I in normal pyloric mucosa from individuals with known Lewis and secretor status was analysed. AAA showed a broad reaction in the superficial pyloric mucosa from secretors and non-secretors, but AAA reactivity was more pronounced in Le(a+b-) individuals. On the other hand, UEA-I stained the superficial pyloric mucosa only from secretor individuals. A staining of deep mucous glands by the lectins was found in all specimens. Both reacted with most human carcinomas of different origin. Slight differences in their binding pattern were observed and may be explained by the different fine-specificities of the lectins.

On-board calibration of bidimensional aperture synthesis radiometers with a large number of antennas by the standard correlated noise injection method is technologically very critical because of the stringent requirements on mass, volume, and phase equalization of the noise distribution network. A novel approach, which makes use of a set of uncorrelated noise sources uniformly distributed in the array, is proposed. Each noise source drives correlated noise only to a small set of adjacent antennas. These sets of antennas are overlapped in order to maintain phase and modulus track along the array. This approach reduces drastically mass and volume of the noise distribution network. Moreover, its phase matching requirement is strongly relaxed because it is only necessary within small sets of adjacent antennas. Power stability of the uncorrelated noise sources is also not a stringent requirement. This procedure allows independent phase and modulus calibration by making use of a reduced number of redundant correlations.

The European Space Agency (ESA) is conducting a feasibility study on MIRAS, a Microwave Imaging Radiometer using two dimensional aperture synthesis, for the mapping of soil moisture and ocean salinity from space. An aircraft breadboard of this instrument is discussed. This paper concentrates on the results achieved following the integration of the prototype. The breadboard consists of an 11 element Y-shaped bi-dimensional L-band interferometer which can be switched to measure the two polarizations. In addition the future activities related to MIRAS are presented. A technology demonstrator of MIRAS is proposed as a first major step towards a future spaceborne sensor.

There is an interest for climatology and meteorology to map hydrometeors, and in particular precipitation, both over the entire globe and across large defined regions. To achieve this goal at the proper spatial and temporal resolution which are required to satisfy the end users needs it has been proposed to use satellite based observations. This paper presents the results of a theoretical study aiming to the research of new concepts for the remote sensing of hydrometeors with emphasis on precipitation. The concept proposed is a Focused Wide band millimeter wave INTERferometer (WINTER-F) comprising a constellation of two small satellites, flying close to each other. The two satellites, which are phase synchronized by the GNSS (Global Navigation Satellite System) signals, perform near field interferometry by passive (radiometer) and active (radar) means. The study comprises the realization of laboratory experiments to check the validity of the theoretical models

In planned intersatellite optical communication systems, the optical payload on board the geostationary satellite will be periodically pointed towards an Optical Ground Station. When the satellite-ground link is established, the turbulence-induced disturbances must be taken into account. The subject of this paper is to assess the statistics for the power fadings that result from the instantaneous point-spread function distortion. Results predicted by an approximate technique which considers the instantaneous point-spread function as a gaussian intensity distribution displaced from the focus due to the angle-of-arrival tilt are compared against results obtained from wavefront simulations produced by fractal generation techniques. The reduction in the cumulative probability of losses that can be obtained by spatial averaging using a multiaperture receiver is also assessed.

A mouse IgM monoclonal antibody FW6 was established after immunization of mice with mucins from human amniotic fluid and was characterized with regard to its binding epitope. According to a series of biochemical criteria the epitope is located on O-linked neutral carbohydrates of M(r) 700,000 and M(r) 570,000 mucins in human amniotic fluid. The epitope is presumed to contain alpha 3/4-linked fucose and terminal beta 3/4-linked galactose that are labile to the fucosidase I from almond emulsion or to the galactosidase from bovine testes, respectively. Immunoreactive fractions of glycan alditols from human amniotic fluid mucins were partially characterized by fast atom bombardment-mass spectrometry and methylation analysis to be composed of monofucosylated polylactosamine-type deca- or nonasaccharides. According to antibody competition studies, inhibition assays with defined carbohydrates and binding assays on neoglycolipids monoclonal antibody FW6 are presumed to recognize a novel epitope that is distinct from known carbohydrate markers of the Lex/Ley family associated with colonic carcinomas. The selective reactivity of this monoclonal antibody to the majority of human colonic carcinomas and its nonreactivity to normal colonic mucosa may render this antibody as a valuable tool in cancer diagnosis or cancer treatment.

MUSE11, DF3 and SM3 MAbs react with a synthetic peptide of 20 amino-acids: VTSAPDTRPAPGSTAPPAHG. This sequence is a tandem repeat domain of the mucin-type glycoprotein coded by the muc-1 gene. MUSE11 and DF3 MAbs immunoreact strongly with mucus cells of the normal surface gastric epithelium of Le(a+b-) non-secretors, but in spite of the peptidic nature of the recognized epitope, the same tissue of Le(a-b+) secretors reacts only after treatment with alpha-fucosidase. These reactions are inhibited by the PNA lectin, which recognizes the T disaccharide antigen (beta Gal 1-3 alpha GalNAc), suggesting that the peptide epitope may be close to the T-saccharide structure. The SM3 MAb reacted on the surface gastric epithelium of all individuals after a more drastic deglycosylation using 20 mM periodate. Computer modeling of the MUC-1 immunoreactive glycopeptide containing the H type-3 trisaccharide alpha Fuc 1-2 beta Gal 1-3 alpha GalNAc- bound to the threonine of the PDTRP-pentapeptide shows that the peptide epitope might be masked when the fucose is positioned over the arginine. Thus, a single fucose linked to the T structure could mask the MUC-1 epitopes. In gastric adenocarcinomas, MUSE11 and SM3 epitopes are expressed in 75% (25/33) and 9% (3/33) respectively, while, after partial deglycosylation by periodate treatment, they are positive in 100% (33/33) and 70% (23/33) of cases, respectively.

The susceptibility to natural-killer-cell lysis and expression of histo-blood-group antigens of 2 clones from a rat colon adeno-carcinoma, of variants derived from them and of 17 human colon carcinoma cell lines were assessed in an attempt to determine if the major glycosidic tissue antigens of epithelial cells could influence the NK susceptibility of tumor target cells of epithelial origin. The rat REGb clone, which is relatively NK-sensitive, expressed higher levels of precursor structures T and Tn and lower levels of H antigenic determinants than the PROb clone, which displays higher resistance to NK-cell lysis. Cell variants were obtained from these 2 clones; it appeared that whether the cell variants were selected on the basis of expression of a blood-group antigenic determinant or on the basis of altered susceptibility to NK-cell lysis, there was a link between increased resistance and higher expression of cell-surface A and H histo-blood-group antigens, or conversely, between increased sensitivity and higher expression of precursor structures. Similar conclusions were obtained upon study of the human cell lines, since a significant correlation was found between the level of expression of T or Tn antigens and sensitivity to NK-cell lysis. A significant relationship was found between the expression of Lewis antigens and increased resistance to NK-cell-mediated cytotoxicity. © 1992 Wiley-Liss, Inc.

Propagation effects at around 830 nm were evaluated in an intermountain scenario in the Canary Islands (Spain) in the framework of an ESA Free Space Optical Communication program. It is concluded that the extinction effects in clear weather conditions do not limit possible ground experiments. The different turbulence-induced effects are found to be reasonably consistent with simplified models. Power scintillation and point-spread function widening can be disturbing effects on the horizontal path.

Periodate pretreatment of paraffin sections of ethanol-fixed gastrointestinal mucosae was used to characterize the carbohydrate or peptidic nature of mucin epitopes by immunoperoxidase. Immunoreactivity of monoclonal antibodies (MAbs) against histo-blood group related carbohydrate epitopes such as A, Lea, Lec, Sialosyl Lea, H type 2, I, T, Tn and sialosyl Tn dramatically decreased or even disappeared after periodate pretreatment of deparaffinized sections. In contrast, the immunoreactivity of MAbs against peptide mucin epitopes such as the gastric M1 mucin epitopes was almost unaffected by this treatment. Moreover, periodate treatment revealed cryptic peptide M1 mucin epitopes and the peptide MUSE11 epitope associated with the 20 amino acid tandem repeat (PDTRPAPGSTAPPAHGVTSA). An increase of cross-reactions of anti-human M1 MAbs with gastric epithelium of different vertebrate species was detected with periodate treatment. Our results suggest that this method can be useful for preliminary characterization of the biochemical nature of mucin epitopes (peptidic or saccharidic) and for demasking peptidic tumour markers which are hidden by saccharide molecules in normal tissues.

In 100 mucinous tumors of the ovary (37 benign, 24 borderline, and 39 malignant), the authors determined by histochemical and immunohistochemical techniques the frequencies and patterns of expression of a total of nine markers of gastric, intestinal, and pancreatobiliary duct epithelial cells. M1, a mucin antigen, and cathepsin E (CaE), an aspartic proteinase, two markers of normal gastric superficial/foveolar epithelial cells, were expressed in 95 and 92 tumors, respectively. Periodic acid-concanavalin A-reactive mucin or pepsinogen (PG) II, markers of gastric mucus neck and pyloric gland cells, were found in 79 tumors. All of these tumors also expressed M1 or CaE. DU-PAN-2 and the N-terminal epitope of gastrin-releasing peptide, markers of normal pancreatobiliary duct cells, were found in 70 and 49 tumors, respectively, and CAR-5 and M3SI, markers of intestinal mucin, were expressed in 51 and 30 tumors, respectively. All tumors expressed at least two of the nine markers studied; none expressed PG I, a marker of gastric chief cells. The mucopeptic cell marker, PG II, was significantly more common in benign and borderline than in malignant tumors (P less than 0.005), whereas CAR-5 and M3SI, markers of intestinal mucin, were expressed significantly more often in malignant than in benign and borderline tumors (P less than 0.001). By electron microscopic examination, many tumor cells had fine structural features characteristic of gastric superficial/foveolar and pyloric gland cells, intestinal columnar or goblet cells, and endocervical cells. The results indicate that gastroenteropancreatic cell differentiation--and, in particular, gastric type differentiation--is a prominent feature of ovarian mucinous tumors.

A prospective study with two gastric biopsies taken several years apart was carried out in 117 subjects with intestinal metaplasia who are of the Lewis(a-b+) phenotype. They are residents of a rural Andean region in Colombia displaying very high rates of gastric cancer. The anomalous expression of Lewis(a) antigens in the metaplastic epithelium carried a significantly increased risk of colonic metaplasia and dysplasia. Such risk was much higher when the simultaneous expression of sulfomucins and Lewis(a) antigen was observed.

The gastric mucin M1 antigens, markers associated with colonic carcinogenesis, have been characterized by new antimucin monoclonal antibodies (MAbs). These MAbs, obtained against mucins isolated from a human ovarian mucinous cyst (MAbs 19M1, 21M1 and 45M1) and from a pancreatic adenocarcinoma (MAb 96RA), were compared with 5 other anti-M1 mucin MAbs described previously, which characterized the a, b, c, d and e mucin M1 epitopes. Using immunoperoxidase, these new MAbs exclusively stained the surface gastric epithelium of normal human gastro-intestinal tract and reacted with fetal, precancerous and cancerous colonic mucosa, but not with normal colon. Immunoradiofixation studies showed that these new MAbs are directed against 3 epitopes (f, g and h) which are different from the a, b, c, d and e mucin M1 epitopes, though present on the same a immunoreactive high-molecular-weight components (greater than 1,000 kDa) with a density of 1.4 by CsCl-density-gradient ultracentrifugation. M1 antigenicity is characterized by a family of 8 different M1 epitopes which were destroyed with beta-mercaptoethanol (except for the f epitope), sensitive to a 5 hr trypsin treatment and resistant to 5 mM periodate (except for the h epitope). Some epitopes (b, c and d) showed increasing immunoreactivity after 20 mM periodate treatment, suggesting cryptic location. In rat-colon adenocarcinomas, M1 mucin epitopes were masked but could be decrypted using high periodate treatment, similar to normal rat gastric mucosa, thus suggesting the absence of drastic changes in the saccharide coat of the peptide mucin portion bearing M1 epitopes. Cryptic location, periodate resistance, sensitivity to protease and conformational behavior strongly suggest that the peptidic core of gastric (or fetal colonic) mucin plays a role in M1 immunoreactivity. Indeed, the resurgence of M1 antigens during colonic carcinogenesis is due to re-expression of the peptide core of gastric (or fetal colonic) mucins.

Organ-specific mucin antigens detected by polyclonal antibodies were first used to characterize abnormal differentiation of gastrointestinal (GI) adenocarcinomas (1,2). These mucin tumour markers can thus be useful as criteria for evaluating the degree of gastric or intestinal differentiation of gastric carcinomas. In addition, some of these mucin antigens are expressed early during GI carcinogenesis where they are associated to premorphological abnormalities (3-5). Consequently, these markers are of importance for studying genetic changes occurring in precancerous mucosa, in which cancer cell transformation can occur. Finally, recent observations have pointed out a putative value of these mucin antigens for screening high risk populations for GI cancers. First of all, we shall define the words: mucin, mucin antigen (or epitopes) and organ-specificity before described abnormal antigen expression during GI carcinogenesis in the cancerous and in the precancerous mucosae and specially concerning their association with premorphological abnormalities.

The design of a Microstrip Test Fixture for TRL calibration, based on mobile, precisely positioned coax-to-microstrip transitions, is described. Experimental results for the measurement of GaAs FET and HEMT chips S-parameters in the 1-40 GHz frequency band are presented, and compared with the manufacturer's available data. Theoretical considerations and experimental results for the repeatability of transitions, based on a useful "error box" model, are also presented.

Results are presented on laser-diode (LD) based intermountain tests carried out as a support activity to ESA's Free-space Optical Communications program to evaluate the Canary Islands (Spain) as an optical communicaton test range. The model predictions of low atmospheric attentuation and turbulence-induced effects were confirmed by a simple link test between observatories, showing that the Canary Islands are a proper site for performing terrestrial experiments of free-space optical communication systems.

Ovarian mucinous cysts, but not ovarian cysts of other histological types, contain common antigens with normal gastric mucosa. By immunodiffusion, antigens of both extracts give identical reactions. Immunofluorescence experiments localize these antigens in the epithelial coat of ovarian mucinous cysts and in the mucous cells of the surface epithelium of the fundic and pyloric gastric mucosa. Images Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8

1. 1. Two major glycoprotein components were released in vitro by rat gastric mucosal cells after 4 hr incubation with radioisotopes: a high molecular weight fraction with the characteristics of a fucomucin and a low molecular weight fraction, the latter having a higher specific radioactivity than the former. 2. 2. Pulse chase experiments indicate that several low and high molecular weight glycoproteins are synthesized simultaneously with no precursor-product relationship between them. 3. 3. Common antigenic determinants, specific to the stomach were found on the 2 fractions, using immunofluorescence, both fractions appeared to be present in the same cells.

The influence of the Rayleigh and Compton contributions to a Mossbauer scattering line is studied. A Mossbauer scattering spectrum of absorption character is theoretically predicted and experimentally observed for iron impurities in beryllium.

The performance of the X-ray — e− coincidence technique for recording depth selective57Fe CEMS spectra was investigated. The technique proved useful for selection of K-shell conversion electrons (7.3 keV) from a beam of back scattered electrons. This makes it possible to observe the depth sensitivity of CEMS spectra recorded with an He/CH4 flow proportional counter.

We defined the chemical structure and the genetic control of the various A or B determinants expressed by pyloric and duodenal epithelial cells by indirect immunofluorescent staining using monoclonal anti-A or anti-B reagents that recognize only certain variants of A or B antigenic determinants.

Integral and analytical formulae are derived for the shape of the background-corrected single resonance scattering line. Nuclear resonance, Rayleigh and Compton scattering processes are taken into consideration. The thickness and resonant isotope abundance dependence of line amplitude and line width is analysed. Due to the filtrational properties of the nuclear resonance scattering process the background-corrected scattering line amplitude reaches its highest value for a very thin sample for which the linewidth is also narrowest. The conclusions derived from the numerical analysis are supported by the experiments. [Russian Text Ignored].

The double resonance scattering process is observed in an enriched hematite by detecting the 6.47 keV conversion X-rays following the nuclear resonance absorption of 14.4 keV γ-rays which were previously recoilless-recoillessly scattered by an enriched metallic iron foil. [Russian Text Ignored].

Integral and analytical formulas are derived for the shape of the Mossbauer dispersion line measured in transmission—scattering geometry. Dispersion spectra are measured for an enriche hematite absorber and enriched metallic iron scatterer by detecting scattered γ-rays, conversion electrons, and conversion X-rays. Very small differences in the resonance energies of the absorber and scatterer are indicated by dispersion spectra measured by detecting scattered γ-rays, conversion X-rays, or conversion electrons. [Russian Text Ignored].

A series of 55 flow cytometric characterized colorectal adenomas was analyzed with four different monoclonal antibodies (Mabs) for the occurrence of M1 antigens (associated with gastric fucomucins) and one Mab for carcinoembryonic antigen (CEA). The antigens were detected with an indirect immunoperoxidase technic on paraffin sections after pretreatment with pronase for M1 antigens and without pretreatment for CEA. The staining pattern revealed different correlations with the various parameters, i.e., size, histologic type, atypia, and ploidy of the adenomas. Especially the cytoplasmic staining of anti-M1, Mab (1-13 M1) correlated well with aneuploidy (R = 0.43; P less than or equal to 0.001) and with the DNA index (R = 0.34; P less than or equal to 0.01). Staining of the anti-CEA Mab only correlated with the size of the adenomas (R = 0.29; P less than or equal to 0.03). It is concluded that the immunoreactivity of Mab (1-13 M1), which significantly correlated with aneuploidy, may be associated with malignant transformation in the adenoma-carcinoma sequence.

We investigated seven different procedures for chemical induction of rat colonic carcinogenesis using: repeated high doses (i) weekly 10 x 15 mg/kg, (ii) quarterly 8 x 15 mg/kg; repeated low doses (iii) weekly 27 x 1.5 mg/kg, (iv) quarterly 8 x 5 mg/kg, (v) quarterly 8 x 1 mg/kg; and single injections of 1,2-dimethylhydrazine (DMH) at (vi) 1 x 40 mg/kg or (vii) 1 x 20 mg/kg. Rats had typical histological precancerous lesions of the colon (dysplasia) and intestinal carcinomas in the six groups receiving a total dose of more than 8 mg/kg DMH. With doses of greater than 120 mg/kg, rats had more cancers, particularly intestinal carcinomas and significantly reduced survival. Rats receiving a single injection of 20 or 40 mg/kg also had histological lesions and colonic carcinomas. The group receiving a 40 mg/kg total dose in a single injection had a significantly higher frequency of colonic lesions per rat and a higher incidence of rats with colonic lesions than groups receiving the same total dose but fractionated. Control rats and groups injected with an 8 mg/kg total dose had no cancers, nor pre-cancerous histological lesions. Thus the carcinogenesis is dose-related, but for the same final dose a single injection gives more histological colonic lesions than several recurrent injections; however, the number of colonic carcinomas and the survival did not vary. This lack of correlation between the number of dysplasia and the number of adenocarcinomas may indicate that dysplasia is not always the precursor lesion of adenocarcinoma. With repeated low doses, we obtained colonic adenocarcinomas after a long period of latency in old rats, thus producing an experimental model with characteristics similar to those found in humans.

The cation distributions in nickel ferrite-aluminates are calculated from the equilibrium conditions and from known cation distributions in nickel ferrite and nickel aluminate. Auf der Grundlage von Gleichgewichtsbedingungen und bekannten Winkelverteilungen der Kationen im Nickel-Ferrit und im Nickel-Aluminat werden die Winkelverteilungen fur Eisen-Nickel-Aluminat berechnet.

Karrowing of the Mossbauer line by resonant filtering in multiple scattering geometry is analyzed. Reduction in linewidth to the value of nearly one gamma may be obtained in a special triple resonance scattering geometry. [Russian Text Ignored].

Immunofluorescence studies showed that human gastric M 1 antigens and intestinal M 3 antigen are associated respectively with the mucus cells of surface gastric epithelium and with the intestinal goblet cells of the normal adult gastrointestinal tract. In the fetus and new born, it was possible to demonstrate by use of double labeling (fluorescein and rhodamine) that some goblet cells of colonic glands contain both the M 1 and M 3 antigens. This ‘fetal-type’ association of M antigens, which could not be found in the normal adult colonic mucosa, was observed in some goblet cells of the transitional mucosa adjacent to human colonic adenocarcinomas. Probably it represents the reappearance of a fetal-type pattern associated with the tumors.

The possible effect of oral 13 cis retinoic acid (13-cis-RA) on the carcinogenic process induced by 28 weekly s.c. injections of 1,2-dimethylhydrazine (DMH) in 34 Wistar rats was investigated. Using immunohistology, precancerous and cancerous stages were compared with the same stages induced by DMH without additional 13-cis-RA in 33 rats. M1 antigens, which characterize modifications in goblet-cell differentiation occurring early in rat colonic carcinogenesis, were used to investigate the possible effect of retinoids on differentiation during precancerous stages. From 3-20 weeks after the start of the experiment, no significant differences were observed in the timing of M1 antigens in the 2 groups of rats. It was also observed that 13-cis-RA had no effect on histological lesions associated with precancerous mucosa, nor on the occurrence of intestinal adenocarcinomas. Thus, under these conditions, oral administration of 13-cis-RA did not significantly inhibit precancerous or cancerous stages of intestinal carcinoma development.

Integral and analytical formulae are derived for the shape of the time independent selective excitation double resonance line and used in the numerical analysis of its thickness and resonant isotope abundance dependence. The conclusions derived from this analysis are supported by a selective excitation double resonance experiment performed for an enriched metallic iron foil. The selective excitation double resonance spectra measured for a natural magnetite show no evidence of an electron hopping relaxation process. [Russian Text Ignored].

Forty-one benign and malignant ovarian tumors and 12 normal ovaries were studied immunologically, with extracts of gastric mucosa as reference, in the presence of antimucosa antisera, adult gastric antipepsinogens (anti Pg I–II, anti Pg III and anti Pg IV) and fetal gastric antipepsinogens (anti Pg IV). Pepsinogens were identified in 7 out of 24 benign tumors, all of the mucinous type and in 1 out of 17 malign tumors. Pepsinogen secretion did not occur in normal ovaries. The potentiality of pepsinogen synthesis by tumoral ovaries was the same as that of other antigens of the gastric or intestinal type as recently found in the same tumors. This potentiality did not seem to be linked to the malignancy of the tumors studied.

The M1 antigens, associated with gastric fucomucin, the early oncofetal precancerous marker for the distal colon, were studied using the immunoperoxidase method in the distal colon. We compared human tumoral mucosa with that of rats during DMH-induced carcinogenesis. In both cases we examined histologically normal mucosa, mucinous hyperplasia, glands with serrated epithelium and hypermature goblet cells like those observed in human hyperplastic polyps, dysplasia, and transitional mucosa. We were able to assess similarities between these rat and human mucosae in terms of the tissue and cell location of these M1 antigens as well as the frequency of occurrence in the different comparative lesions. Thus, we demonstrated that such similarities can be observed not only at a histologic level, but also on a molecular level. The presence of M1 antigens in the human distal colon is comparable to mucous modifications induced by a chemical carcinogen, as observed during DMH-induced carcinogenesis in the rat.