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Biomedical subjects

O Brandonisio

Publications and source records attributed to O Brandonisio.

At least 37 records · Page 2Linked to original sources
PubMed1999

Inducible nitric oxide synthase and nitric oxide production in Leishmania infantum-infected human macrophages stimulated with interferon-gamma and bacterial lipopolysaccharide.

Nitric oxide produced by an inducible nitric oxide synthase constitutes one of the main microbicidal mechanisms of murine macrophages and its importance is now being recognized for human macrophages. In this study we evaluated inducible nitric oxide synthase expression, nitric oxide release, and parasitocidal ability of Leishmania infantum-infected monocyte-derived human macrophages. The inducible nitric oxide synthase was detected by immunofluorescence and western blotting and nitric oxide production was measured by the Griess reaction for nitrites. Parasite killing was microscopically evaluated by fluorescent dyes. Experiments were performed on macrophages with or without previous stimulation with recombinant human interferon-gamma and bacterial lipopolysaccharide. Inducible nitric oxide synthase expression and nitric oxide release were higher in Leishmania-infected stimulated macrophages than in uninfected cells or infected cells without previous stimulation. Nitric oxide production and parasitocidal activity against Leishmania infantum were reduced in macrophages treated with the nitric oxide synthase inhibitor L-N(G) monomethylarginine. These results suggest a microbicidal role for nitric oxide in human leishmaniasis, with the possible practical application of immunological or pharmacological regulation of nitric oxide synthesis in the treatment of this infection.

Animals↗
PubMed1999

Intestinal protozoa in HIV-infected patients in Apulia, South Italy.

Protozoa are important enteric pathogens in patients with human immunodeficiency virus (HIV) infection. In this study the prevalence of intestinal protozoa in 154 HIV-infected patients, with or without diarrhoea, in our region (Apulia, South Italy) was evaluated between December 1993 and February 1998. In the majority of patients CD4+ T cell count was below 200/microl. The overall prevalence of intestinal protozoa was 43/154 (27.92%). Twenty-eight (43.08%) out of 65 patients with diarrhoea and 15 (16-85%) out of 89 non-diarrhoeic patients were parasitized. In particular, in the group of 65 patients with diarrhoea the following protozoa were identified: Cryptosporidium parvum in 14 (21.54%), Blastocystis hominis in 7 (10.77%), microsporidia in 6 (9.23%), Giardia lamblia in 4 (6.15%) and Isospora belli in 1 (1.54%). Three patients were Cryptosporidium parvum-microsporidia co-infected. In patients without intestinal symptoms, prevalence was 3/89 (3.37%) for Cryptosporidium parvum, 9/89 (10.11%) for Blastocystis hominis, 1/89 (1.12%) for microsporidia and 2/89 (2.25%) for Giardia lamblia. A significant (P<0.001) correlation was observed between protozoan infection and the presence of diarrhoea. In particular, Cryptosporidium parvum and microsporidia infections were significantly (P<0.001) and P = 0.046, respectively) associated with diarrhoeal illness. Moreover, the majority of cases of cryptosporidiosis were first diagnosed in the periods of heaviest rainfall. Therefore, drinking water contamination may be a possible source of human infection in our area.

Adult↗
PubMed1999

Diagnosis of a case of gastric anisakidosis by PCR-based restriction fragment length polymorphism analysis.

A set of genetic markers, based on PCR-RFLPs of three diagnostic restriction enzymes (Hhal, Hinfl and Taql), which proved to be suitable for the identification of the species of the genus Anisakis, was used for the first molecular identification of a larva obtained by endoscopy in a case of gastric anisakidosis, in a 51 year old woman from Southern Italy. The analysis of the restriction profiles obtained allowed the larva to be identified as Anisakis pegreffii, one of the three sibling species of the A. simplex complex. PCR-RFLP proved to be a cost-effective and reliable tool for the exact identification of Anisakis larvae recovered from infected humans.

Anisakiasis↗
PubMed1998

Evaluation of nitric oxide production by Leishmania infantum-infected dog macrophages.

Protozoa of the genus Leishmania (L.) infect reticuloendothelial cells of several mammalian species, including dogs, in which they often give rise to a chronic, not self-healing visceral disease. Since the parasitocidal mechanism of macrophages towards Leishmania in dog has not yet been well investigated, in this work we have evaluated in Leishmania infantum-infected macrophage cultures from 10 healthy dogs, killing capacity and nitric oxide (NO) production, in terms of nitrite (NO2) levels. Parallel experiments were performed on macrophages stimulated with both Concanavalin A (ConA)-activated PBMC supernatants and Salmonella typhimurium lipopolysaccharide (LPS), and in the same conditions, but in the presence of the NO synthase inhibitor L-N monomethylarginine (L-NMMA). In L. infantum-infected macrophages, nitric oxide production was observed at a concentration significantly higher after stimulation with both Con A-activated PBMC supernatants and LPS than that observed in uninfected cells cultured in medium alone, or infected cells unstimulated or stimulated by PBMC supernatants or LPS alone, respectively. Moreover, NO production was abolished in the presence of the NO synthase inhibitor L-NMMA. Finally, killing of Leishmania by macrophages was significantly reduced in the presence of L-NMMA.

Animals↗
PubMed1998

Evaluation of killing, superoxide anion and nitric oxide production by Leishmania infantum-infected dog monocytes.

Protozoa of the genus Leishmania infect reticuloendothelial cells of several mammalian species, including dogs, in which they often give rise to a chronic, not self-healing visceral disease. The parasitocidal mechanism of peripheral blood monocytes towards Leishmania in the dog has not been investigated in detail. Consequently, Leishmania infantum-infected monocyte cultures of healthy dogs were evaluated using the following parameters: (1) phagocytosis and killing capacities; (2) oxidative burst, in terms of superoxide anion (O2-) release, and (3) nitric oxide (NO) activity, in terms of nitrite (NO2-) production in the presence or absence of the NO synthase inhibitor NG-monomethyl-L-arginine (NGMMLA). Parallel experiments were performed on monocytes stimulated with supernatants of concanavalin A-activated PBMC and on unstimulated monocytes. The amount of IFN-gamma in PBMC supernatants used for monocyte activation was determined by a biological assay on a canine Madin Darby cell line. Results demonstrated that phagocytosis, killing capacity and O2- production significantly increased in monocytes stimulated with supernatants, in comparison with unstimulated cells. A positive correlation was observed between the killing capacity, the O2- production and the amount of IFN-gamma in PBMC supernatants employed for monocyte activation. No significant differences were observed in NO production between unstimulated and stimulated cultures, or between the same cultures with and without NGMMLA. Finally, the killing percentage was similar in the presence or absence of NGMMLA, suggesting that in this experimental model peripheral blood dog monocytes lack NO-mediated killing.

Animals↗
PubMed1997

Giardiasis in HIV: a possible role in patients with severe immune deficiency.

We report the epidemiological, clinical and therapeutic characteristics of giardiasis in a population of HIV-infected patients with diarrhoic syndrome. During the period between 1988 and 1995, 720 HIV-patients with diarrhoic syndrome were evaluated. Fecal specimens were submitted to parasitological examination according to the Ritchie formalin-ethil acetate centrifugal sedimentation method and stained with iodine. Samples also underwent modified Ziehl-Neelsen staining and standard bacteriologic testing. Cystis of G. intestinalis were identified in stool sample of 25 patients. Two patients were classified as in stage A2 and 23 in C3. Mean CD4 values of patients with giardiasis (26.9 cells/mmc) were compared with those of 65 patients from whom, during the study, was isolated Cryptosporidium parvum (63.12, cells/mmc): the difference resulted highly significant (p < 0.001). Among the patients with full-blown AIDS, giardiasis occurred following a single previous AIDS-defining event in 13 inividuals, in seven and in five subjects giardiasis was the 3rd and, respectively, the 4th relevant AIDS-defining condition. Death occurred within the following 2 months in nine patients and within 6, 12 and 24 months in seven, six and two patients, respectively; at present only three AIDS patients are still alive. In general, G. intestinalis in HIV+, is not considered a major cause of enteritis; nevertheless, in our experience enteritis due to G intestinalis is a frequent event among AIDS patients, especially in the most advanced stage of disease, irrespectively of the risk factor. The increase in mean survival of AIDS patients will probably lead to a progressive emergence of this pathogen which could determine a severe diarroic syndrome with hydro-electrolytic impairments.

AIDS-Related Opportunistic Infections↗
PubMed1996

Prevalence of Cryptosporidium in children with enteritis in southern Italy.

Cryptosporidium parvum is a protozoan which causes self-limiting diarrhea in immunocompetent subjects, and severe life-threatening disease in immunocompromised patients. Cryptosporidiosis is more common in developing countries and in infants. In this paper we have evaluated the prevalence of C. parvum in 368 hospitalized children with enteritis, of whom 359 were immunocompetent and 9 HIV-infected. Stool specimens were concentrated by sedimentation and stained with a modified Ziehl-Neelsen method. Cryptosporidium parvum oocysts were found in 7 (1.90%) out of 368 subjects. Six of these were immunocompetent (with an infection rate in this population of 1.67%) and 1 HIV-infected, asymptomatic except for diarrhea. In all children symptoms of enteritis and oocyst excretion cleared within 10 days. These results indicate that the prevalence of C. parvum as a causative agent of diarrheal illness in hospitalized immunocompetent children is rather low in our region (Apulia, South Italy).

AIDS-Related Opportunistic Infections↗
PubMed1996

Evaluation of polymorphonuclear cell and monocyte functions in Leishmania infantum-infected dogs.

Leishmania infantum is the causative agent of canine leishmaniasis in the Mediterranean area. The aspects of the canine immune response which may explain the chronic severe disease in these animals have not been well investigated. Therefore, in this work we have evaluated the parasite killing ability by circulating polymorphonuclear (PMN) cells and monocytes in dogs with spontaneous leishmaniasis and in healthy dogs. Moreover, in order to analyse the mechanisms responsible for killing activity, we evaluated the oxidative burst of circulating PMN cells, in terms of O2- and H2O2 production. The killing ability of infected dog PMN cells and monocytes was significantly lower than in a group of healthy dogs and a group of infected dogs treated with meglumine antimoniate and without symptoms of leishmaniasis. Superoxide anion and hydrogen peroxide production by PMN cells was significantly lower in a group of Leishmania-infected dogs than in healthy dogs, suggesting that these mediators may be involved in the reduced killing activity of infected dogs.

Animals↗
PubMed1996

Leishmania donovani lipophosphoglycan (LPG) inhibits respiratory burst and chemotaxis of dog phagocytes.

Lipophosphoglycan (LPG) is the major glycoconjugate of Leishmania promastigote surface membrane. Previous studies on human and murine models have demonstrated that this molecule is involved in the attachment and survival of Leishmania in the host cells. Dog is the main reservoir of Leishmania strains responsible for human leishmaniasis in Italy. Since no studies have been performed on the LPG-canine phagocyte interactions, we investigated the LPG effects on dog phagocyte functions by evaluating: 1) the chemotactic activity of peripheral monocytes and polymorphonuclear (PMN) cells, in terms of cellular polarization; 2) the PMN cell respiratory burst, by measuring superoxide anion and hydrogen peroxide production. Results demonstrated a significant reduction of metabolic and chemotactic activity in LPG-preincubated cells, thus emphasizing the ability of this molecule to impair also the canine phagocyte responses.

Animals↗
PubMed1995

Parasite escape mechanisms: the role of Leishmania lipophosphoglycan on the human phagocyte functions. A review.

Protozoan parasites of the Leishmania genus are the causative agents of important diseases in humans and animals. During their life cycle in vertebrate hosts, protozoa are able to live and proliferate within phagolysosomes of host phagocytic cells. The capacity to live in this hostile environment is likely due to the cell surface glycoconjugate expression. In particular, lipophosphoglycan (LPG), a major surface glycoconjugate of Leishmania promastigotes, has been reported to play an active role in protecting parasites within phagolysosomes via the impairment of killing mechanisms. In this review, the authors emphasize some novel LPG-mediated escape mechanisms of promastigotes from human phagocyte responses, such as the impairment of oxidative burst and of chemotactic activity. In the light of these findings, the knowledge of biological actions of LPG may be useful in order to prepare a vaccine against human leishmaniasis, using LPG defective avirulent mutant strains.

Animals↗
PubMed1995

Cyclospora in AIDS patients: not always an agent of diarrhoic syndrome.

The present study reports the clinical features of two AIDS patients infected by Cyclospora. According to our observations, Cyclospora in AIDS can be responsible both for gastroenteritis and for asymptomatic infections with spontaneous rapid clearance. In addition, and undiagnosed circulation of this agent in Italy could be hypothesized: neither patient had a past history of foreign travel. These are the first two cases in AIDS described in Italy.

AIDS-Related Opportunistic Infections↗
PubMed1995

[Leishmania-macrophage interactions: role of cytokines and molecules co-involved in killing].

In this review we have summarized the main data concerning Leishmania-macrophage interactions, with particular emphasis on receptors involved in adhesion, activating or deactivating cytokines and toxic molecules responsible for parasite killing. At present it is also known that a different T helper (Th)1- or Th2-cell response may be critical for the outcome of Leishmania infection in human and in murine models. Therefore, we have mentioned the recent studies on cytokines, such as IL-2, which are able to cause the switch from a Th2, disease-promoting immune response, to a Th1, protective response. In fact, in the light of these findings, these molecules may be used in the future for immunotherapeutical or immunoprophylactic purposes.

Animals↗
PubMed1995

Intestinal microsporidiosis in AIDS patients with diarrhoeal illness in Apulia (south Italy)

Microsporidia are intracellular parasitic protozoa very common in immunocompromised patients in many parts of the world. There is a scarcity of data on the prevalence of these parasites in Italy. In this study we examined stool samples of 56 HIV+ patients with diarrhoea to find microsporidial spores, using the light microscopy Ryan modified trichrome stain. Microsporidia were found in one out of 56 patients, who was Cryptosporidium coinfected. Intestinal microsporidiosis seems to be less frequent in AIDS patients from Italy than in those from other countries.

AIDS-Related Opportunistic Infections↗
PubMed1994

Impairment of the human phagocyte oxidative responses caused by Leishmania lipophosphoglycan (LPG): in vitro studies.

Lipophosphoglycan (LPG), a surface glycoconjugate of Leishmania promastigotes, has been reported as playing an active role in protecting the parasite within phagolysosomes, by an impairment of monocyte oxidative responses. In this study the effect of LPG on the oxidative burst of human peripheral monocytes, eosinophils and neutrophils was evaluated. Our results demonstrated that either superoxide anion (O2-) or hydrogen peroxide (H2O2) release by LPG-pretreated cells was diminished, emphasizing the ability of this glycoconjugate to impair the oxidative activity of all phagocytes.

Animals↗
PubMed1993

Prevalence of cryptosporidiosis in HIV-infected patients with diarrhoeal illness.

Protozoans of the genus Cryptosporidium may cause serious diarrhoeal illness in immunocompromised hosts and especially in HIV-infected patients. In this study we have evaluated the frequency of Cryptosporidium in stools of 51 HIV-infected patients with diarrhoea. Laboratory diagnosis of cryptosporidiosis was performed of faecal samples concentrated by a formalin-ether sedimentation technique and stained by a modified cold Ziehl-Neelsen method. Results demonstrated that 17 (33.3%) of these patients were infected with Cryptosporidium. Moreover, Cryptosporidium infection was the first clinical marker of AIDS in 7 cases. Our data show that the prevalence of this parasitosis in HIV-infected people seems to be higher in our region (Apulia, South Italy), compared to other areas of the world.

AIDS-Related Opportunistic Infections↗
PubMed1992

Canine leishmaniasis in the Gargano promontory (Apulia, South Italy).

We examined 444 dogs by visiting farms and peripheral districts on the Gargano promontory (Province of Foggia, Apulia, South Italy). Clinical examination and immunofluorescence antibody test for leishmaniasis were performed. Bone marrow and lymph node samples obtained from 25 dogs with positive serological test were cultured on Tobie-Evans medium. The results obtained show both a higher seropositivity rate for canine leishmaniasis (14.4%) and a higher percentage of asymptomatic dogs with positive serological test (53.1%) compared to previous research in the same area. Seven strains isolated from infected dogs belonged to Leishmania infantum species zymodeme Montpellier 1. None of 82 sera of humans living in close contact with infected dogs were positive for leishmaniasis.

Animals↗
PubMed1991

HIV-infection and in vivo lipopolysaccharide-induced release of cytokines. An amplified mechanism of damage to the host.

Bacterial lipopolysaccharides (LPS) or endotoxins are potent triggers of the cytokine (CK) cascade. These CKs are immune mediators which produce many biological effects and could play a detrimental rather than beneficial role in the host. In this review emphasis will be placed on the participation of two CKs, tumor necrosis factor [TNF-alpha and interleukin (IL-1) beta], in the pathogenetic development of HIV infection. We have found that TNF and IL-1 circulate in exaggerated amounts in the blood of HIV-infected subjects from the earliest phases of infection. Furthermore, we have observed a strict correlation between plasma LPS and IL-1 beta levels, thus indicating that endotoxins could account for the production of CKs in the course of HIV infection. Finally, the demyelinating role of TNF-alpha either in experimental models or in the course of AIDS dementia complex is outlined.

Animals↗