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M Baccarini

Publications and source records attributed to M Baccarini.

70 records · Page 4Linked to original sources
PubMed1985

In vitro natural cell-mediated cytotoxicity against Candida albicans: macrophage precursors as effector cells.

Bone marrow cells, cultured in L-929 CSF, consist of cells of granulocyte and macrophage lineages. Cells of the granulocyte lineage are known to be cytotoxic for Candida albicans. In this paper we report that macrophage precursor cells also display strong cell-mediated cytotoxicity against the yeast form of the dimorphic fungus C. albicans. The macrophage precursors responsible for this activity are nylon wool-nonadherent, nonphagocytic cells and lack asialo GM1 surface antigen. A purified population of macrophage precursors (greater than 95%) was obtained by means of Percoll density centrifugation. The interaction of these purified effectors with the target yeast cells was analyzed at a single cell level, and their activity was compared with that displayed by cells of the granulocytic series derived from the same bone marrow culture. Macrophage precursor cells proved to be more effective in binding the target cells and showed the same killing ability as the granulocytes: macrophage precursors were not damaged by contact with the target, in contrast to that which happened with granulocytes. In a long-term colony-forming unit assay, in fact, granulocytic cells showed a decrease over time in their ability to inhibit the growth of C. albicans, probably due to cell damage and death after the interaction with the target. In contrast, no loss of activity was observed with the macrophage precursor fraction. The same macrophage precursor cells also proved able to exert good natural killer activity against YAC-1 lymphoma cells, but not against P815 mastocytoma cells, as reported previously. The macrophage precursor cells, when cultivated in vitro to mature macrophages, lost completely their natural cytotoxicity against C. albicans and YAC-1 cells. The implications of these findings, as well as the possible role in vivo of such a precursor cell population during an infection, are discussed.

Animals↗
PubMed1985

Modulation of polymorphonucleate-mediated cytotoxicity against Candida albicans by thymosin alpha 1.

In the present work we analyze the effects of thymosin alpha 1 treatment on the number and the candidacidal activity of murine polymorphonuclear leukocytes. The data we obtained showed that the treatment with thymosin alpha 1 (100 micrograms/Kg s.c.) 10, 8, 6, 4 and 2 days before the assay may result in a significant numerical augmentation of circulating polymorphonucleates in the peripheral blood, as well as of their candidacidal activity when measured in vitro in both a 4-h cytotoxicity assay and a CFU inhibition assay against Candida albicans microorganisms. On the other hand, a single dose of thymosin alpha 1 (500 micrograms/Kg s.c.) 3 days before the assay resulted in a significant decrease of the candidacidal activity of mouse polymorphonucleates. The data are discussed with regard to the immunomodulating capacity of thymosin alpha 1 and to our previously reported observations concerning the ability of the drug to modulate the resistance against systemic Candida albicans infection.

Animals↗
PubMed1984

Enhancement of natural killer cell activity in mice by treatment with a thymic factor.

The administration of a thymic factor, thymostimulin (TP-1), to mice resulted in considerable augmentation of natural killer (NK) cell activity as measured in a short-term assay against 51Cr-labeled YAC-1 target cells. Conditions suitable for detection of the thymostimulin-induced boosting of NK included multiple daily exposures to TP-1 (50 micrograms/kg), and peak levels of reactivity were observed at 2-4 days after discontinuation of treatment. A strict age-dependency of the effect was also observed, with optimal augmentation of NK-cell activity when TP-1 was administered to mice at 4-6 weeks of age. The effect was not limited to TP-1 treatment but was also observed on administration of another thymic factor (thymosin alpha 1). The activated cells responsible for the increased natural cell-mediated cytotoxicity appeared to be typical murine NK cells, judging by both functional and antigenic criteria.

Age Factors↗
PubMed1984

Combined effects of cyclophosphamide and thymostimulin treatment on the in vitro natural killer and candidacidal activity of murine spleen cells.

Two different natural cell-mediated cytotoxic reactions (lysis of YAC-1 and killing of Candida albicans) in vitro were studied in mice undergoing treatment with cyclophosphamide (Cy), thymostimulin (TP-1) or a combination of both. Enhancing effects followed the combination regime in the microbial natural cell-mediated cytotoxicity assay, whereas in the NK assay the effect of TP-1 appeared to be antagonistic to that of Cy. The possible mechanisms involved are discussed.

Animals↗
PubMed1983

Correlation between in vivo and in vitro studies of modulation of resistance to experimental Candida albicans infection by cyclophosphamide in mice.

Mice receiving a single injection of cyclophosphamide (150 mg/kg) 1 to 6 days before inoculation with viable Candida albicans showed an increased susceptibility to the challenge accompanied by a reduction in peripheral blood polymorphonuclear leukocytes and lymphocytes as well as in spleen cellularity. Several immunological in vitro functions also appeared to be dramatically depressed. Most of these hematological and functional parameters returned to control values by day 9 after cyclophosphamide administration, at a time when resistance to C. albicans infection appeared to be unchanged. However, when exposure to cyclophosphamide occurred 12 to 21 days before inoculation with the live yeast, enhanced resistance was observed with the majority of the animals surviving challenge. To gain some insight into the mechanisms underlying this late increase in resistance to C. albicans infection after cyclophosphamide administration, we analyzed a series of immunological functions, including the in vitro candidacidal activity of polymorphonuclear neutrophils and plastic-adherent and nonadherent spleen cells as well as the activity of natural killer cells and alloreactive T lymphocytes. The results show that a numerical rebound of blood polymorphonuclear neutrophils and the appearance of a highly candidacidal cell population in the spleen may be among the factors underlying the late increase in resistance to C. albicans after administration of cyclophosphamide.

Animals↗
PubMed1983

Natural cell-mediated cytotoxicity against Candida albicans induced by cyclophosphamide: nature of the in vitro cytotoxic effector.

We have recently reported the in vivo modulation of resistance to experimental Candida albicans infection by cyclophosphamide (150 mg/kg intraperitoneally) in mice and have shown that increased resistance to the microbial challenge occurs 12 to 21 days after treatment with the drug (Bistoni et al., Infect. Immun. 40: 46-55, 1983). The event is accompanied by the appearance of a highly candidacidal cell population in the spleen and the activation of a subpopulation of natural cytotoxic effectors reactive in vitro against YAC-1 tumor cells. We now provide evidence that these anti-YAC-1 cytotoxic effectors are clearly distinct from the cyclophosphamide-induced candidacidal effectors, which seem to belong to a macrophage-monocyte lineage. The enhanced cytotoxic activity induced by cyclophosphamide was not restricted to C. albicans but was also exerted against a panel of Candida strains.

Animals↗
PubMed1983

Comparison between natural reactivity (NR) against Candida albicans and natural killer (NK) activity against YAC-1 tumour cells.

Cytotoxic activity against Candida albicans was measured in vitro in a 4-h 51Cr-release assay. The levels of reactivity correlated well with the number of polymorphonuclear cells in the effector population, being augmented by the enrichment of polymorphonuclear granulocytes. To exclude the possible role of contaminating natural killer cells, natural killer activity against tumour cells was compared with natural reactivity against Candida albicans in vitro. The findings indicate that there are many differences between these reactivities including organ and strain distribution, age dependency, adherence to nylon, and susceptibility to modulation by immuno-adjuvants and to treatment with anti-Thy 1.2 antiserum plus complement. These data further define in vitro polymorphonucleate-mediated cytotoxicity against Candida albicans on the basis of the above-mentioned criteria and clearly demonstrate that this in vitro reactivity could not be due to the presence of contaminating natural killer cells in the effector cell population.

Age Factors↗
PubMed1983

Relationships among tumor load, route of tumor inoculation, and response to immunochemotherapy in a murine lymphoma model.

The combined effects of nonspecific immunostimulation with Candida albicans (CA) and chemotherapy were studied in (BALB/cCr X DBA/2Cr)F1 and (C57BL/6Cr X DBA/2Cr)F1 mice bearing virus-induced LSTRA lymphomas. Paradoxically, animals treated with a relatively high number of tumor cells responded better to therapy with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) than those challenged with a low number of tumor cells. However, the majority of mice subjected to low initial tumor load were cured when they were treated with chemotherapy or chemotherapy plus booster injection of CA at a relatively "late" stage of the disease, i.e., when high tumor load was present in tumor-bearing hosts. It has been shown that this phenomenon, provisionally called high tumor load protection, occurs when the animals are challenged ip but not when they are challenged iv with the tumor and is abolished by total-body gamma-irradiation. Moreover, marked host protection can be attained when immunostimulated mice, inoculated iv with lymphoma cells, are subjected to simultaneous challenge with high inocula of the same tumor ip, followed by BCNU administration. These data stress the importance of the peritoneal cavity for successful CA plus drug treatment and suggest that optimal tumor "antigen load" should be present at the time of CA and/or BCNU administration.

Animals↗
PubMed1983

Phagocytic killing of Candida albicans by different murine effector cells.

Three major phagocytic populations in the mouse were tested in vitro for killing of Candida albicans by means of 51Cr release assay: early inflammatory peritoneal polymorphonuclear cells (PMN), unfractionated or adherent spleen cells and resident peritoneal macrophages (PEC). Considerable candidacidal activity was found in the early inflammatory neutrophil and adherent spleen cell populations. On the contrary, only limited activity was found to be associated with resident peritoneal macrophages. The phagocytic killing apparently involved multiple mechanisms.

Animals↗
PubMed1982

A radiolabel release microassay for phagocytic killing of Candida albicans.

The chromium release technique for quantifying intracellular killing of radiolabelled Candida albicans particles was exploited in a microassay in which murine and human phagocytes acted as effectors under peculiarly simple conditions. At appropriate effector: target ratios and with a 4 h incubation, up to 50% specific chromium release could be detected in the supernatant with no need for opsonization or lysis of phagocytes. This simple microassay permits easy-to-perform, simultaneous testing of a variety of different phagocytes even if only available in limited amounts, and provides an objective measurement of intracellular killing of Candida albicans.

Animals↗
PubMed1982

Cellular mechanisms underlying the adjuvant activity of Candida albicans in a mouse lymphoma model.

Inactivated Candida albicans (CA) possesses strong anti-tumor activity when combined with cytoreductive chemotherapy in a mouse lymphoma model. In the present study, experiments were performed in order to elucidate the mechanism(s) underlying CA immunoadjuvant activity. In vivo chemotherapy studies proved that the synergistic anti-tumor effects were lost in athymic (nu/nu) mice and were also abrogated by radiations. In vitro tests did not suggest a major involvement of natural cytotoxic effectors such as macrophages and natural killer cells nor did CA effects appear to be mediated by induction of interferon. It was concluded that the immunoadjuvant activity of CA largely relies on host responses against tumor-associated transplantation antigens with no major involvement of natural resistance immune mechanisms.

Adjuvants, Immunologic↗
PubMed1982

The role of the peritoneal cavity in successful treatment of a murine lymphoma with chemotherapy and non-specific immunostimulation.

The influence of the route of administration and treatment schedule of a yeast immunoadjuvant, Candida albicans (CA) on the degree of success achieved with an immunochemotherapy regimen in a virus-induced murine lymphoma has been evaluated. To this end, histocompatible CD2F1 mice received IP or IV inoculations of LSTRA lymphoma cells and were subjected to various treatments with inactivated CA and bis,1,chloroethyl nitrosourea (BCNU). The results showed that CA may significantly increase the antitumor efficiency of BCNU when (a) the tumor is inoculated IP and not IV; (b) CA is administered before (on day -14) and after (on days +1 and/or day +8) LSTRA challenge; (c) CA is given IP as a post-tumor treatment. To ascertain whether the immunoadjuvant effect was anatomically restricted to the peritoneal cavity (PC), spreading of IP injected lymphoma was studied by means of LSTRA cells labeled with 3-5'iodo-deoxyuridine 125I (125IUdR) and tumor bioassay in spleen, lung, kidney, liver, and PC of recipient mice. The results showed that IP tumor challenge led to early (1 h) generalized neoplasia in both untreated and CA-pretreated hosts. Therefore, the combined antitumor effects of chemotherapy and CA are not restricted to the PC but rather the result of systemic immunity. In conclusion, in our system the PC seems to be a preferential site for eliciting generalized antilymphoma host responses markedly amplified by selected schedules of immunoadjuvant administration.

Adjuvants, Immunologic↗
PubMed1981

[Euglycemizing effect of partial jejuno-ileal resection in rats treated with streptozotocin].

Resection of about 50% of the small intestine was performed in rats diabetised with streptozotocin. The first results show that this operation leads to normalisation of sugar metabolism that is partly referable to partial malabsorption, but above all to loss of weight. Current knowledge with regard to the relation between diabetes and obesity is discussed and an account is given of the modern surgical approaches to the treatment of major obesity. Lastly, the suggestion is made that limited digestive bypass may be indicated in cases of insulin-independent diabetes where weight loss and control of blood sugar cannot readily be achieved by conventional medical management.

Animals↗
PubMedDate not supplied

[Traumatic duodenal lesions].

The authors refer their experience about five cases of traumatic duodenal lesions. They confirm the casual relationship between delayed diagnosis, often due to inaccurate clinical-radiological evaluation, and prognosis. They emphasize the opportunity to perform a simple suture and decompression by nasogastric tube, to selected cases.

Duodenum↗
PubMedDate not supplied

[Papillo-sphinctero-plasty in benign obstruction of the terminal choledochus].

The indications for papillosphincteroplasty in benign obstruction of the terminal choledochus are explained. This technique is certainly preferable to drainage via a T tube--a method no longer applied in a personal series. Lastly, it is stated that the primary transduodenal approach is better than that via choledochotomy. Excellent results were obtained in 62% of cases, good results in 31%, and poor results due to recurrent cholangitis in 3%. Acute pancreatitis is the most dangerous complication, but was very rarely observed.

Ampulla of Vater↗