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Biomedical subjects

E Falcieri

Publications and source records attributed to E Falcieri.

86 records · Page 5Linked to original sources

A simple immunoperoxidase method for detecting enteric adenovirus and rotavirus in cell culture.

A technique which includes the use of indirect immunoperoxidase antibody (IPA) has been developed for detecting enteric adenovirus and rotavirus antigens in cell cultures and has been compared with immunofluorescence antibody assay (IFA). The IPA technique was as sensitive as the IFA. The number of positive cells detected by both techniques in tissue cultures was the same; false positive results were not observed. The applicability of IPA in clinical virology is discussed.

Adenoviridae↗

[Multidisciplinary study of 2 cases of herpetic encephalitis].

Two different cases of fatal Herpes simplex type 1 encephalitis are reported. A presumptive diagnosis of herpes encephalitis was made on the basis of clinical symptoms and of neurodiagnostic evidence (EEG - CT) and was confirmed by serological and virological tests. The electron microscopy of the nuclei of the infected cells supported the diagnosis of HSV encephalitis.

Adult↗

[Syphilitic pleuritis. Description of a clinical case].

A rare case of luetic pleurisy diagnosed in a patient with tertiary syphilis, when the aetiological agent was discovered in the pleuritic exudate is described. The spirochaetes, first revealed by dark field microscopy, were studied further under the electron microscope, using negative colouring and fine sections.

Humans↗

Evaluation of a new latex agglutination test for detecting human rotavirus in faeces.

Four methods for detecting rotaviruses (latex agglutination, electron microscopy, immunofluorescence and ELISA) have been compared on 57 faecal samples from children with acute diarrhoea. Complete agreement among the four techniques was found in 38 samples. One sample was positive by ELISA and latex agglutination but negative by the other two. For all the other samples there was agreement among three of the techniques only. In a blocking ELISA test, samples positive by ELISA only, turned out to be falsely positive. Assuming true positive or negative for those samples for which at least three techniques were in agreement, electron microscopy, ELISA and latex agglutination were more sensitive (96 per cent) than immunofluorescence (84 per cent). Electron microscopy was the most specific (96.4 per cent), followed by immunofluorescence (92.9 per cent), ELISA (89.4 per cent) and latex agglutination (85.9 per cent).

Diarrhea↗

[Ultrastructural analysis of the effect of antimicrobial drugs on the development of Chlamydia trachomatis in cells cultured in vitro].

The Authors report the results of an ultrastructural study of the developmental cycle of Chlamydia trachomatis in cell cultures in vitro in the presence of inhibitors of te synthesis of DNA (mitomycin-C), RNA (actinomycin-D and rifampin) and proteins (oxytetracycline and chloramphenicol). The chlamidiae were grown to IUDR-pre-treated McCoy cell cultures and the drugs were added to the medium either immediately after the infection (in the presence of "elementary bodies" only) or after the appearance of the first "initial bodies" (14 hours after infection). The appearance of "initial bodies" or their multiplication was completely prevented in the infected cell cultures in the presence of mitomycin-C, actinomycin-D, rifampin and oxytetracycline added immediately after the infection or 14 hours after the infection, respectively. In the presence of chloramphenicol the appearance of "initial bodies" or their multiplication was possible, but their differentiation into "elementary bodies" was completely inhibited.

Anti-Bacterial Agents↗

[The replication cycle of Chlamydia trachomatis and Chlamydia psittaci: ultrastructural analysis].

An ultrastructural comparative analysis is reported on the replication cycle of six strains of Chlamydia trachomatis, recently isolated, and Chlamydia psittaci strain 6BC, grown in cell cultures. Important morphological distinctions of the bacterial walls are documented. In Chlamydia trachomatis the cell wall seems more rigid. This causes, during the morphogenesis of the elementary body, its separation from the cell membrane with formation of an electron transparent space, which is not demonstrable in Chlamydia psittaci. As a result of this process, the appearance of "ghosts" and "mini reticular bodies" is documented. Budding and multiple fission are suggested as possible mechanisms of replication of Chlamydia trachomatis, in coexistence or/as alternative to binary fission.

Cell Wall↗

Inhibition of a complete replication cycle of human cytomegalovirus in actinomycin pre-treated cells.

The study of human cytomegalovirus (HCMV) in cultures of human embryo lung fibroblasts, pre-treated with actinomycin D, has shown that under these conditions the virus infection does not proceed beyond the 'early' events of the virus replication cycle. In the same experimental conditions the growth of poliovirus type I, vaccinia virus and herpes simplex type I virus, was completely unaffected. These results suggest that the complete HCMV replication cycle requires some cellular function(s) between early transcription of the input virus genome and virus DNA synthesis.

Antigens, Viral↗

Apoptotic pathways depend on the target enzymatic activity and not on the triggering agent.

Molt-4 human leukemia cells were triggered to apoptosis by various agents with different mechanisms of action. Staurosporine, a protein kinase C (PKC) inhibitor; camptothecin, a topoisomerase I blocking drug; and tiazofurin, an inhibitor of inosine 5'-phosphate dehydrogenase (IMPDH), were used. Ultrastructural analysis showed morphologic changes characteristic of apoptosis that were very similar for all three agents. Nevertheless, DNA oligonucleosomic fragmentation was not detectable by agarose gel electrophoresis. However, a genomic DNA cleavage appeared after pulse-field gel electrophoresis (PFGE) in cells treated with these agents for 24 h. Furthermore, in situ nick translation (NT) showed a finely spotted nuclear labelling in staurosporine-treated cells and a compact fluorescence after camptothecin incubation. In tiazofurin-treated cells an intermediate pattern was found. Therefore, apoptotic agents with different mechanisms of action induced the formation of large genomic DNA fragments and very similar ultrastructural changes. Therefore, both phenomena and the closely related apoptosis progression depend on target cell machinery and not on the triggering agent.

Apoptosis↗

5-(2-Ethyl-phenyl)-3-(3-methoxy-phenyl)-1H-[1,2,4]triazole (DL-111-IT) and related compounds induce apoptotic patterns in cultures of human tumor cell lines.

5-(2-Ethyl-phenyl)-3-(3-methoxy-phenyl)-1H-[1,2,4]triazole (DL-111-IT) and related compounds were extensively studied as anti-gestational agents and some of these molecules were also described as inhibitors of ornithine decarboxylase. Polyamine depletion has been frequently related to the induction of apoptosis and consequently we investigated DL-111-IT and analogs for this effect in myeloid (HL60), neuroblastic (SK-N-MC) and epithelial (BeWo) human tumor cell lines, by means of electron microscopy and DNA electrophoresis. HL60 and SK-N-MC appeared notably sensitive to apoptosis, whereas BeWo responsiveness was variable and frequently associated with necrosis. Our results indicate that the contragestational effect of DL-111-IT and analogs is associated with apoptotic deletion of chorionic tissue and that these molecules, due to their effect on human tumor cell lines, can be considered as antiblastic lead compounds.

Apoptosis↗

C2C12 murine myoblasts as a model of skeletal muscle development: morpho-functional characterization.

In this study, the differentiation of C2C12 cells, a primary line of murine myoblasts, was investigated by a multiple technical approach. Undifferentiated cells, and those at intermediate and final differentiation times, were studied at the reverted microscope, by conventional and confocal immunofluorescence, and by transmission and scanning electron microscopy. The general monolayer architecture changed during differentiation from fusiform or star-shaped cells to elongated confluent cells, finally originating long, multinucleated myotubes. Sarcomeric actin and myosin are present also in undifferentiated myoblasts, but progressively acquire a structured pattern up to the appearance of sarcomeres and myofibrils at about 5 days after differentiation induction. Myotubes show a particular positivity for actin and myosin, and M-cadherin, an adhesion molecule characteristic, as known, of satellite cells, also seems to be involved in their assembling. Rare apoptotic patterns, as evidenced by the TUNEL technique, appear during myoblast maturation.

Animals↗