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.     

3-Mercaptopropionic acid administration increases the affinity of [H]Quinuclidinyl benzilate binding to membranes of the striatum and cerebellum

It is known that quinuclidinyl benzilate (QNB) binds specifically and with high affinity to the cholinergic muscarinic receptor and that behaves as a potent antagonist of this receptor.

We have analysed -[³H]QNB binding to rat CNS membranes after the administration of the convulsant 3-mercaptopropionic acid (MP) (150 mg·kg⁻¹, i.p.). The studies were done in rats killed at two stages: during and after seizures. No changes in [³H]QNB binding to hippocampus and cerebral cortex membranes were found. [³H]QNB binding increased about 40 and 80% in striatum and cerebellum membranes, respectively. The changes were observed both in seizure and postseizures states. The study was extended to the assay of [³H]QNB binding kinetic constants in the anatomical areas modified by the convulsant. The analysis of the saturation curves indicated an increase in the binding affinity but no change in the number of binding sites. Hill number values were near the unit suggesting a non-cooperative interaction between the ligand and the receptor, and the labelling of a homogeneous population of receptor sites.

The results suggest the participation of some cholinergic pathways in the development and maintenance of MP-induced seizures.     

Airborne fungi in an Italian rice mill

Summary Studies employing volumetric spore trap (VSP) and gravity settling culture plates (GSC) were conducted in order to analyse the air spora of a rice mill at Pavia, Italy, from October-December 1988. Results revealed a variety of fungal spores belonging to different genera and including recognized rice pathogenic fungi. The most frequent genera by GSC method includedAcremonium, Alternaria, Aspergillus, Aureobasidium, Cladosporium, Epicoccum, Fusarium, Helminthosporium, Mucor, Nigrospora, Penicillium, Rhizopus, Trichoderma, Trichothecium, and some unidentified fungi. Environmental assessment of fungal spores by VSP revealed that the most prevalent fungi were:Alternaria, Cladosporium, Epicoccum, Helminthosporium, Nigrospora, Pyricularia, Tilletia and hyaline, dark and coloured types of ascospores and basidiospores. Airborne fungal spore concentrations were particularly high (5,000–6,000 spores/m³) in the rooms of the rice mill where the initial stages of rough rice transformation take place, and dropped to 2,500 spores/m³ in the last room, where workers are. During a temporary interruption of the working processes, air spora concentration dropped below 1,000 spores/m³.Cladosporium, Epicoccum andNigrospora spores were predominant in all subdivisions of the indoor environments of the rice mill.     

Respiratory electron transport activity in plankton of the Weddell and Scotia Seas during late spring — early summer: relationships with other biological parameters

Summary As a means to estimate potential oxygen consumption, profiles of elctron transport system (ETS) activity were made along three transects across the Weddell-Scotia Confluence zone (WSC) and the marginal ice zone (which overlapped in part) during the EPOS leg 2 cruise of the RV Polarstern. The integrated ETS activity between 0 and 100 m depth (referred to in situ temperatures) ranged from 261 meq (mili-electron equivalents) m^–2 day^–1 in the WSC to 45 meq m^–2 day^–1 in the southernmost stations at 62° S. The temporal changes in the overall distribution of ETS activity were small compared with the spatial variations. The main feature of the ETS activity distribution was the presence of maxima located in the WSC, coinciding with peaks of phytoplankton biomass. Different relationships between ETS and chlorophyll a concentration in these maxima appeared to be related to diatom or flagellate dominance. Vertically integrated ETS activities were significantly correlated with chlorophyll a and paniculate organic carbon concentrations, primary production and bacterial thymidine uptake.Data presented here were collected during the European Polarstern Study (EPOS) sponsored by the European Science Foundation     

Effect of TSH in human thyroid cells: evidence for both mitogenic and antimitogenic effects.

The well-known mitogenic effects of TSH observed in vivo on the thyroid are not always reproducible of human thyroid cells in vitro where conflicting results have been obtained. In order to clarify this issue, we have used primary cultures of human thyroid cells obtained from normal tissue and maintained in serum-free medium for several days. In this in vitro model we have studied the effect of TSH on growth by measuring three different parameters: [3H]-thymidine incorporation, cell counts, and DNA measurement. Monolayer cultures were plated at both low and high cell density (2 x 10(4) and 8 x 10(4) cells/25 mm well, respectively). Although at either cell density cultures were equally able to functionally respond to TSH in terms of cAMP accumulation a significant growth response to TSH was observed only in low density cultures. In high density cultures TSH had an antimitogenic effect. Moreover, TSH potentiated the mitogenic effect of insulin only in low density cultures. In contrast to TSH, FCS induced a similar proliferative response at both high and low cell density. Following TSH stimulation, cAMP content was always increased, paralleling the effect of growth in low density but not in high density cultures. The cAMP analogues dibutyryl-cAMP and 8-bromo-cAMP, as well as cholera toxin and forskolin, did not mimic the mitogenic effect of TSH but had an antiproliferative effect. In addition, these agents blunted the proliferative effect of insulin. These data suggest that in thyroid cells TSH is able to elicit both a mitogenic and an antimitogenic effect depending on the environmental conditions such as cell density.(ABSTRACT TRUNCATED AT 250 WORDS)     

Detection of complex alleles by direct analysis of DNA heteroduplexes

DNA molecules derived from three alleles of the HLA-DRB3 locus and differing from each other at several nucleotide sites were denatured and cross-hybridized. Each allelic combination was found to generate a pair of heteroduplexes of different mobility. Their retardation as compared to homoduplexes was proportional to the number of mismatches. In each heteroduplexes pair the component possessing the highest number of Pyr-Pyr oppositions was the most retarded. The results are those predicted by a theoretical model implying a correlation between base-pair opening and bending of the DNA double helix. These observations introduce a new HLA typing method at the genomic level and indicate an experimental approach to the analysis of the superhelical DNA conformation as related to different types of base oppositions.     

Effect of applied and internal hormones on vitrification and apical necrosis of different plants cultured in vitro

Development of vitrification and apical necrosis was followed in Camellia sinensis, Gerbera jamesonii, Malus domestica and hybrid Populus tremula x P. alba shoots cultured in vitro on Murashige & Skoog (MS) medium with different concentrations of growth regulators. High humidity in the culture vessels and excess of BA in the medium were found to be the major factors influencing vitrification. Lack of exogenous cytokinin in the medium during successive subcultures induced apical necrosis in poor-rooting species (Malus domestica, Camellia sinensis). The level of internal phytohormones (ABA, IAA, IPA, 2iP, Z, ZR) was determined in the apple shoots by means of ELISA. The content of internal cytokinins in the vitrified apple shoots was several times greater than in normal ones, which supports the hypothesis that excess of cytokinins, inducing rapid divisions of cells in meristems in the atmosphere with high humidity, is responsible for vitrification. Apical necrosis of the plantlets that appeared after cultivation on cytokinin-free medium is the result of deficiency in endogenous hormones in apple shoots and this being confirmed by analysis of endogenous hormones in apple shoots.Abbreviations BA benzyladenine - BHT butylated hydroxy-toluene - ABA abscisic acid - IAA indole-3-acetic acid - ELISA enzyme-linked immunosorbent assay - IPA isopentenyladenosine - 2iP isopentenyladenine - NAA naphthyl-3-acetic acid - TBS trishydroxymethylaminomethane buffered saline - TLC thin layer chromatography - Z zeatin - ZR zeatin riboside     

Spring and summer hosts for Pieris rapae in Southern Spain with special attention to Capparis spinosa

The suitability of different host plants for Pieris rapae L. in the South of the Iberian Peninsula, was studied in relation to host plant phenology, female behaviour, and larval development. Capparis spinosa is the only host plant available during the dry season of the year in the area studied. D. virgata, R. raphanistrum, H. incana and S. alba being suitable spring hosts. Comparative studies on mortality, larval development and larval growth between C. spinosa and the spring hosts revealed no significant differences.

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Résumé L'adéquation de différentes plantes comme hôtes de P. rapae a été examinée en fonction de la phénologie des végétaux, du comportement de la femelle et du développement larvaire dans le sud de la péninsule ibérique. Pendant la saison sèche, C. spinosa est la seule plant convenable dans la zone étudiée. Diplotaxis virgata, Raphanus raphanistrum, Hirschfeldia incana et Sinapis alba sont des hôtes printaniers convenables. La mortalité, le développement et la croissance larvaires ne sont pas différentes sur C. spinosa et sur les hôtes de printemps.

     

Purification and characterization of aspartate aminotransferase from the thermoacidophilic archaebacterium Sulfolobus solfataricus

Aspartate aminotransferase from the archaebacterium Sulfolobus solfataricus, a thermoacidophilic organism isolated from an acidic hot spring (optimal growth conditions: 87 degrees C, pH 3.5) was purified to homogeneity. The enzyme is a dimer (Mr subunit = 53,000) showing microheterogeneity when submitted to chromatofocusing and/or isoelectric focusing analysis (two main bands having pI = 6.8 and 6.3 were observed). The N-terminal sequence (22 residues) does not show any homology with any stretch of known sequence of aspartate aminotransferases from animal and bacterial sources. The apoenzyme can be reconstituted with pyridoxamine 5'-phosphate and/or pyridoxal 5'-phosphate, each subunit binding 1 mol of coenzyme. The absorption maxima of the pyridoxamine and pyridoxal form are centered at 325 and 335 nm, respectively; the shape of the pyridoxal form band does not change with pH. The enzyme has an optimum temperature higher than 95 degrees C, and at 100 degrees C shows a half-inactivation time of 2 h. The above properties seem to be unique even for enzymes from extreme thermophiles (Daniel, R. M. (1986) in Protein Structure, Folding, and Design (Oxender, D. L., ed) pp. 291-296, Alan R. Liss, Inc., New York) and lead to the conclusion that aspartate aminotransferase from S. solfataricus is one of the most thermophilic and thermostable enzymes so far known.