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Biomedical subjects

P Marelli

Publications and source records attributed to P Marelli.

15 recordsLinked to original sources
PubMed1999

Liver cancer imaging: the need for accurate detection of intrahepatic disease spread.

The last ten years have seen dramatic changes in the therapeutic approach to both primary (i.e., hepatocellular carcinoma: HCC) and secondary (i.e., metastatic lesions) focal liver malignancies. This has been due to the increasing proliferation of new modalities, including percutaneous ablative therapies (ethanol injection: PEI; radiofrequency: RF; laser; microwaves), angiographic therapies (segmental chemoembolization; hypoxic perfusion) and liver transplantation (OLT), in addition to a greater acceptance of pre-existing modalities (resection; systemic chemotherapy). Thus, a main aim of current medical management is to select for each patient the therapeutic modality which will provide the highest success rate, fewest risks and lowest costs for each given situation. However, in order to decide on the appropriate therapeutic choice, the accurate diagnosis of neoplastic lesions by means of one or more imaging modalities (ultrasound: US; computed tomography: CT; magnetic resonance: MR) is mandatory. This imaging work-up can be viewed as having three purposes: lesion detection, lesion characterization, intrahepatic and extrahepatic cancer staging. The present paper is concerned primarily with the imaging approach to liver lesion detection.

Carcinoma, Hepatocellular↗
PubMed1993

BCG-activated NK cells regulate the antibody response to SRBC and restore immune reactivity to PPD in BCG-infected mice.

C57B1/6 mice show a significant increase in the number of natural killer (NK) cells in the peritoneal cavity, four days after intraperitoneal infection with Mycobacterium bovis strain BCG. Cell transfer experiments demonstrated that BCG-induced NK cells are able to depress the induction of antibody response to an unrelated antigen (i.e., sheep red blood cells) in recipient mice. The involvement of macrophages, B and T cells in the phenomenon was ruled out by using different purification steps. In addition, BCG-induced NK cells were shown to be able of partially restoring the DTH response to PPD in recipient mice that were anergic to the latter antigen as a consequence of intravenous infection with large doses of BCG.

Animals↗
PubMed1993

[Vocal recognition in dental and oral radiology].

Speech reporting benefits by units which can recognize sentences in any natural language in real time. The use of this method in the everyday practice of radiology departments shows its possible application fields. We used the speech recognition method to report orthopantomographic exams in order to evaluate the advantages the method offers to the management and quality of reporting the exams which are difficult to fit in other closed computed reporting systems. Both speech recognition and the conventional reporting method (tape recording and typewriting) were used to report 760 orthopantomographs. The average time needed to make the report, the legibility (or Flesch) index, as adapted for the Italian language, and finally a clinical index (the subjective opinion of 4 odontostomatologists) were evaluated for each exam, with both techniques. Moreover, errors in speech reporting (crude, human and overall errors) were also evaluated. The advantages of speech reporting consisted in the shorter time needed for the report to become available (2.24 vs 2.99 minutes) (p < 0.0005), in the improved Flesch index (30.62 vs 28.9) and in the clinical index. The data obtained from speech reporting in odontostomatologic radiology were useful not only to reduce the mean reporting time of orthopantomographic exams but also to improve report quality by reducing both grammar and transmission mistakes. However, the basic condition for such results to be obtained is the speaker's skills to make a good report.

Humans↗
PubMed1990

Polyclonal B cell activation in ankylosing spondylitis.

The peripheral blood lymphocyte response of patients with ankylosing spondylitis (AS) to several polyclonal B cell activators was investigated. No differences were found in the reactivity to pokeweed mitogen and protein A between patients and controls; in contrast, the peripheral blood lymphocyte response to Staphylococcus aureus strain Cowan I (SAC) was significantly higher in patients with AS than in controls. This responsiveness was not influenced either by the presence of the HLA-B27 antigen or by environmental factors or associated diseases, and it was higher in patients with active AS than in those with inactive disease. The percentage of circulating B cells was normal. The responses to T cell mitogens and the percentages of T cell subpopulations were similar in patients and in controls. The peripheral blood lymphocyte hyperactivity of patients with AS to SAC was associated with an increased in vitro production of immunoglobulins.

Adult↗
PubMed1989

B-cell-mediated depression of the granulomatous response to BCG in mice.

The depression of the granulomatous response to Mycobacterium bovis strain BCG in mice infected intravenously with 2 x 10(7) CFU of the microorganism turned out to be mediated by various types of cells arising at different times after infection. Anti-PPD B lymphocytes were found to play a major role at Day 1 after infection and to be no longer effective 4 days later. At this time the depression was mediated by anti-idiotype B lymphocytes, whereas T lymphocytes proved to be involved in later phases of the infectious process. These results show that B lymphocytes may be of critical importance in the regulation of cell-mediated immune reactions to this facultative intracellular parasite.

Animals↗
PubMed1989

Analysis of Mycobacterium tuberculosis genoma and production of a recombinant protein containing specific B and T cell antigenic determinants--new approaches to second generation antituberculosis vaccines.

Tuberculosis is still a major health problem in almost all over the world. Thus, new directions in basic and applied research of tuberculosis are under investigation in several laboratories. In this paper, we provide recent data obtained in our laboratory with the recombinant DNA technology which allow a systematic survey of the microbial genome. Screening of the M. tuberculosis genomic DNA library in the phage lambda gt11 expression vector, using E. coli as surrogate host, has evidenced the possibility of producing recombinant M. tuberculosis proteins recognized by sera from tuberculosis patients and by specific monoclonal antibodies. Using this technology, we have isolated a recombinant protein (molecular weight 130 kilodaltons) which is identified by a murine monoclonal antibody recognizing a mycobacterial cell wall antigenic determinant present on a mycobacterial protein. This protein is only present on the mycobacterial species related to the tuberculosis complex (M. tuberculosis, M. bovis, M. africanum) and does not crossreact with nonpathogenic Mycobacteria. Since the immune response to mycobacterial infections is cell-mediated, the question arises about the use of M. tuberculosis-specific T lymphocytes to screen this gene bank. Thus, the recombinant mycobacterial protein isolated by antibodies has been then used to stimulate the proliferation of T lymphocytes from patients with tubercular pleuritis. This experiment indicates that the recombinant protein contains antigenic determinants recognized by T cells. Moreover, such protein is able to elicit delayed type hypersensitivity skin reaction in mice immunized or infected with M. tuberculosis and M. bovis. Finally, gene mapping and hybridization studies with native M. tuberculosis DNA confirme the mycobacterial nature of the recombinant DNA insert. Thus a good candidate for the prophylaxis and the immunodiagnosis of tuberculosis has been identified. The identification and selection of genes encoding antigenic determinants recognized by mycobacteria-specific T cells with protective functions will allow in the near future the construction by genetic engineering of recombinant vaccines effective in the control of this disease. This paper will briefly discuss the present strategy used in our laboratory to reach this goal.

Animals↗
PubMed1986

B and T lymphocytes regulated by idiotype anti-idiotype interactions inhibit delayed-type hypersensitivity to BCG in mice.

Mice infected subcutaneously with 2 X 10(7) CFU of Mycobacterium bovis strain BCG (BCG) were able to mount a specific DTH response, whereas mice infected intravenously with the same dose of microorganisms were not. The suppression turned out to be mediated by id+ anti-PPD B lymphocytes, which arose very early during the infectious process and induced anti-id B lymphocytes. These cells were found at Day 4 after infection and exerted their effect by activating antigen-specific suppressor T lymphocytes, which affected the efferent phase of the DTH response. These results clearly indicate that the activation of a complex immunosuppressive circuit represents a mechanism by which BCG may interfere with the host's immune response already during the very early phases of infection.

Animals↗
PubMed1985

Staphylococcus aureus-induced suppression of contact sensitivity in mice: suppressor cells elicited by polyclonal B-cell activation are regulated by idiotype--anti-idiotype interactions.

Staphylococcus aureus strain Cowan I, a strong polyclonal B-cell activator (PBA), inhibited contact sensitivity to oxazolone in mice when administered 24 hr before sensitization. This suppression was mediated by idiotype-positive (Id+) B lymphocytes, which arose very early during the sensitization process and induced anti-Id B cells. These cells were found at Day 3 of the sensitization process and exerted their effect by activating antigen-specific suppressor T lymphocytes, which affected the efferent phase of the immune response. S. aureus strain Wood 46, which lacks of the ability to act as a PBA, was unable to inhibit contact sensitivity. These results indicate that PBA may play an important role in the regulation of cell-mediated immune reactions.

Animals↗
PubMed1985

Polyclonal B cell activators inhibit contact sensitivity to oxazolone in mice by potentiating the production of anti-hapten antibodies that induce T suppressor lymphocytes acting through the release of soluble factors.

Polyclonal B cell activators (PBAs) such as purified protein derivative, lipopolysaccharide, Staphylococcus aureus strain Cowan I (StaCwI), and Pseudomonas aeruginosa inhibit contact sensitivity to oxazolone in mice when given 24 h before sensitization. This suppression, transferable from immunodepressed animals to oxazolone-sensitized recipients with immune serum, has been shown to be due to the early appearance of anti-hapten antibodies. These antibodies elicit T suppressor cells which release soluble factor(s) capable of inhibiting the passive transfer of contact sensitivity.

Animals↗
PubMedDate not supplied

Depression of the immune responsiveness in mice treated with thioacetamide after antigen exposure.

The effects of the weak carcinogen thioacetamide (TAA) on the mouse immune response have been investigated. TAA administration up to 1 day after antigen priming markedly suppressed the antibody response to both T-dependent (sheep erythrocytes) and T-independent (trinitrophenyl-Ficoll) antigens; the compound was ineffective when given 3 or 4 days after immunization. A significant suppression of the in vitro lymphoproliferative response to the B-cell mitogen S. aureus Cowan I was evident from 3 to 48 h after TAA treatment. On the other hand, cell-mediated immune response to oxazolone was suppressed by TAA at each time tested, including that of challenge. The in vitro lymphoproliferative response to concanavalin A was decreased 12 h after TAA administration only, when adenosine deaminase activity within lymphocytes was increased. Furthermore, TAA is endowed with anti-inflammatory activity, as shown by the decreased footpad swelling and by evaluation of the inflammatory cell infiltration upon carrageenan injection. Taken together, these findings suggest selective TAA interaction with multiple targets within the immune system, including B- and T-lymphocytes, while non-specific cytotoxicity can be reasonably ruled out, since hematological determinations and phenotypic analysis of spleen lymphocyte subsets showed no relevant changes.

Acetamides↗
PubMedDate not supplied

Percutaneous ethanol injection of autonomously functioning thyroid nodule.

Percutaneous ethanol injection (PEI) is proposed for treatment of autonomously functioning thyroid nodule, especially for small-mid-sized solitary nodules, for patients refusing the other methods or not proving responsive to radioiodine, or for patients with non toxic nodule. The injection is performed under color Doppler sonography guidance, evaluating the most vascularized areas of the tumor where to primarily inject ethanol solution with 21-22 gauge needles. Serum TSH, FT4, FT3 and TG levels are measured before each treatment session and 3,6,12,24 and 36 months after the end of therapy. Complete remission was achieved by different authors in 86% of cases and the efficacy of response was shown to be inversely proportional to the nodule volume. When TSH remains undetectable, a second cycle of PEI can be performed. If there is complete lack of blood flow signals on color or power Doppler with persisting thyroid hyperfunction, sonographic contrast media can be administered i.v. to assess residual areas of intranodal hypervascularity. In patients with unsuppressed TSH levels before treatment, hormonal changes cannot be used as marker response. Disappearance of nodular hypervascularity at color Doppler sonography and complete normalization of the scintigraphic pattern is usually observed in all cases. PEI is generally well tolerated; no recurrences of the disease and no cases of hypothyroidism have been reported.

Ethanol↗
PubMedDate not supplied

[Pseudomonas aeruginosa: immunotypes and drug resistance].

Serotyping of Pseudomonas aeruginosa by Fisher's schema has been used to study the prevalence of particular immunotypes among strains of P. aeruginosa obtained from clinical specimens. About 78% of the isolates were serotypable and about 22% were not. Immunotypes 2 and 6 turned out to be the most prevalent, whereas immunotypes 5 and 7 were the least frequent. Immunotypes 2, 5, 6 and 7 did not vary significantly as far as frequency in the various sources is concerned, with the exception of immunotype 2, which was significantly less frequent in isolates from the expectorated sputum. In such isolates immunotype 3 was significantly more frequent than in other sources, whereas immunotype 4 was significantly more frequent in isolates from the feces. It was next investigated whether a correlation exists between antibiotic susceptibility and particular immunotypes. A high percentage of the non-typable strains and of those belonging to immunotypes 2 and 6 proved to be resistant to the antimicrobial agents tested.

Humans↗