Serological recognition of HLA-DR allodeterminant corresponding to DNA sequence involved in gene conversion

HLA class 11 molecules were isolated from mouse L cells transfected with a DR gene and an allele, 52a, of locus DR III from an HLA-homozygous cell line, AVL, of the DR3 haplotype. The isolated molecules were found to possess a new allospecificity, named TR81. This specificity behaved allelic to the previously described DR III locus. The TR81 specificity was also present on the DR I gene product of the DR3 haplotype. The nucleotide sequence of the gene encoding TR81 differs from TR81-negative DR genes of the DRw52 family in only two codons, both located in the regions known to be involved in a gene conversion event. Consequently, the following conclusions can be formulated. (a) TR81 is a bi-locus specificity and allelic to TR22 only in its DR III locus localization. (b) The TR81 specificity is the phenotypic counterpart of the gene conversion event which led to the generation of the DR I gene of the DR3 haplotype. (c) One or both individual amino acid substitutions in the first domain of the DR chain are responsible for the TR81 allospecificity. (d) Since TR81 is expressed on the DR I chain of the DR3 haplotype, it is possible that TR81 and DR3 represent the same serological specificity.     

DNA flow cytometry of endoscopically examined colorectal adenomas and adenocarcinomas

DNA ploidy of 64 colorectal adenomas and 49 adenocarcinomas, examined endoscopically, was studied by flow cytometry. We found DNA aneuploidy in none of the 105 normal mucosa samples (0%), in 20 adenomas (31%), and in 36 adenocarcinomas (74%). DNA ploidy of adenomas correlated with size (P = 0.02) and degree of dysplasia (P less than 0.01) but not with histologic type. Adenomas had a 45% incidence of DNA aneuploid stem lines in the DNA index range of 0.80-1.20, compared with 8% in the case of adenocarcinomas. The distribution of the DNA index values of adenocarcinomas was approximately normal, with a mean value 1.63 +/- 0.28. The mean DNA index for the three cases of "carcinoma in adenoma" with invasion of the stalk of the adenoma was 1.52 +/- 0.18. These results, using DNA flow cytometry, provide evidence for the progression of colorectal adenoma to adenocarcinoma. The classification of adenomas according to DNA ploidy may be information of considerable practical value to the clinician in predicting risk of further adenomas and/or risk of cancer.     

Fura-2 secretion and sequestration in macrophages. A blocker of organic anion transport reveals that these processes occur via a membrane transport system for organic anions

Fura-2, loaded into J774.2 macrophages as the acetoxymethyl ester, is sequestered into intracellular vacuoles within 90 min after the beginning of the loading at 37 degrees C. The dye is also efficiently secreted from the cells. Sequestration and secretion of fura-2 reduce the accuracy of measurements of cytosolic free Ca2+ concentration in this cell line. Fura-2 is also sequestered and secreted by J774.2 when the dye is loaded into the cytoplasm as the pentapotassium salt by reversible permeabilization of the plasma membrane. Regardless of the mechanism by which fura-2 is loaded into the cytoplasm, both sequestration and secretion are prevented by 2.5 mM probenecid, a blocker of organic anion transport. Probenecid has no effect on resting or stimulated cytosolic free Ca2+ levels or on FcR-mediated phagocytosis. These findings suggest that macrophages express a transport mechanism for the anionic form of fura-2. This transport system is responsible for the clearance of fura-2 from the cytoplasm of this cell type. Furthermore we suggest that use of probenecid to block secretion and intracellular sequestration of fura-2 may overcome problems arising in the application of this Ca2+ indicator to macrophages and perhaps to other cell types.     

Tumor induction and life shortening in BC3F1 female mice at low doses of fast neutrons and X rays

Extension of previous investigations at this laboratory regarding life shortening and tumor induction in the mouse has provided more complete dose-response information in the low dose region of X rays and neutrons. A complete observation of survival and late pathology has been carried out on over 2000 BC3F1 female mice irradiated with single doses of 1.5 MeV neutrons (0.5, 1, 2, 4, 8, 16 cGy) and, for comparison, of X rays (4, 8, 16, 32, 64, 128, 256 cGy). Data analysis has shown that a significant life shortening is observable only for individual neutron doses not lower than 8 cGy. Nevertheless, assuming a linear nonthreshold form for the overall dose-effect relationships of both radiation qualities, an RBE value of 12.3 is obtained for the 1.5 MeV neutrons. The induction of solid tumors by neutrons becomes statistically significant at individual doses from 8 cGy and by X rays for doses larger than 1 Gy. Linear dependence on neutron dose appears adequate to interpret the data at low doses. A separate analysis of ovarian tumor induction substantiates the hypothesis of a threshold dose for the X rays, while this is not strictly needed to interpret the neutron data. A trend analysis conducted on the neoplasm incidence confirms the above findings. Death rates have been analyzed, and a general agreement between the shift to earlier times of these curves and tumor induction was found.     

The role of morphometry in the cytology of well-differentiated hepatocarcinoma and cirrhosis with atypia

A morphometric study was performed on 200 nuclei per case in six well-differentiated hepatocarcinomas and in six cirrhoses with cytologic atypia, using samples obtained by fine needle aspiration (FNA) biopsy of the liver. The parameters measured were the nuclear area, the nuclear perimeter and the maximum nuclear diameter. The nuclei of well-differentiated hepatocarcinomas could be distinguished from those of cirrhoses on the basis of the larger size and greater anisonucleosis of the former. A statistical analysis (using a two-sided t-test) of the means of the parameters showed significant differences between the two diagnostic groups. These results suggest that morphometric analysis can help in the differential diagnosis between well-differentiated hepatocellular carcinoma and cirrhosis with cytologic atypia in FNA biopsy samples.     

小鼠腹水型肝癌H22a细胞浆内磷蛋白磷酸酶活力调节的研究

小鼠腹水型肝癌细胞胞浆内磷蛋白磷酸酶对磷酸化的组蛋白、酪蛋白、鱼精蛋白具有脱磷酸化活力,而对小分子底物P-Ser、P-Thr、P-Tyr、PNPP等无活力。二价金属离子Mn~(2+)、Co~(2+)、Mg~(2+)对酶有明显激活作用,而Zn~(2+)、F~-、Pi对酶有明显抑制作用。代谢中间物G-6-P、G-1-P、F-6-P、F-1.6-2P、ATP、ADP、GTP对酶有抑制作用,而磷酸化氨基酸和环核苷酸对酶活影响很小。还试验了碱性蛋白质和酸性蛋白质对酶活力的影响,肝素和组蛋白均对酶活力有抑制作用,当两者混和后,其抑制作用会相互抵消。     

Successional pathways of Mediterranean evergreen vegetation on Sicily

The Mediterranean evergreen vegetation of Sicily, comprised in the belt of the Quercetea ilicis, occupies a large part of the island. Human intervention (cutting, fire, pasture) has brought about a degradation of the natural vegetation. This study is based on our phytosociological research of the Quercetea ilicis belt on Sicily.

With the ‘habitat comparison’ method, the dynamical relations between the different vegetation units have been defined.

We distinguish the following stages, with reference to their vegetation structure:

• a herbaceous stage formed by steppic vegetation, preceded by various types of nitrophilous-ruderal vegetation on abandoned fields;

• a garrigue stage dominated by half-shrubs;

• a macquis stage with various distinct plant communities, four communities being important in regressive successions, and three in progressive ones;

• a woodland and shrub-woodland stage with three different substages: pre-existent forests, present woodlands, and woodlands which tend towards the final, stable stage of vegetation (potential natural vegetation).

The dynamic relationships both in progressive and regressive successions have been synthesized in a scheme. In this scheme we have shown the main stages of the vegetation in their dynamics and we have constructed different series of vegetation types in two altitudinal belts, which are determined by varying environmental conditions of today.

The results also show that in some cases the progressive series follow different pathways than the regressive series, and the final stage of the progressive series is different from the original vegetation.

     

Liver peroxisomes in newborns from clofibrate-treated rats. II. A biochemical study of the recovery period.

The fatty-acyl-CoA beta-oxidation (FAO) and catalase activities, as well as membrane fluidity of liver peroxisomes of newborns from normal and clofibrate-treated rats were studied during the recovery period, ie, throughout the first week of postnatal life. In the test animals the enzyme activities, which are significantly higher than controls at birth return to normal levels showing a somewhat different time course with FAO rapidly decreasing to control values within three days but with catalase still higher than controls at day 6. The half-life and degradation rate (Kd) of FAO are identical to those calculated by us for the whole organelles and to those reported by others for total catalase in normal or clofibrate-treated adult animals in the presence of catalase inhibitors. Soluble catalase shows turnover values which are similar though not identical to those of FAO, while total catalase has a very long half-life and a low Kd. Peroxisomal membrane fluidity, as determined by fluorescence anisotropy of 1-anilinonaphthalene-8-sulfonate (ANS) bound to purified peroxisomal fractions is higher in tests than in controls, recovering normal values within 6 days. Our results demonstrate that liver peroxisomes of rats prenatally exposed to clofibrate return to control conditions within about 1 week. The turnover parameters of enzymes and the membrane fluidity values are discussed in terms of disposal mechanism(s) for the excess of induced peroxisomes.