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Biomedical subjects

S Gatti

Publications and source records attributed to S Gatti.

At least 37 records · Page 2Linked to original sources
PubMed2001

Asymptomatic amoebic infection: Entamoeba histolytica or Entamoeba dispar? That is the question.

Two cases of amoebic infection were diagnosed in a heterosexual couple. The cases, a Frenchman with previous trips to various African countries and his sexual partner, a Cameroonese woman immigrant living outside the community, were both asymptomatic; the infection had been diagnosed by chance in the man at the time of his employment in a hospital kitchen. Based on what is known of the epidemiology of amoebic infection, it may be acquired and then transmitted within a couple via the indirect faecal-oral route or, in greater likelihood, by sexual practices. Both amoebic isolates were characterised by isoenzyme electrophoresis as non-pathogenic Entamoeba dispar, zymodemel. Other diagnostic tools, such as ELISA direct stool antigen detection tests and serological assays were employed, confirming the diagnosis of E. dispar infection. Given there are a number of asymptomatic cyst passers of Entamoeba histolytica, besides human carriers of saprophyte E. dispar, we stress the importance of applying, when possible, advanced protocols of diagnosis to distinguish the microscopically identical pathogenic species from the non-pathogenic one.

Animals↗
PubMed2001

[Pathogenic protozoans in man: differential characterization of Entamoeba histolytica/Entamoeba dispar complex, Acanthamoeba spp., Microsporidia].

The review summarizes the results in the main parasitological topics of our Lab: amoebic infections due to Entamoeba histolytica/Entamoeba dispar complex and to Acanthamoeba spp. respectively, and human infections caused by microsporidia. Different rapid and advanced techniques have been included in the standardized diagnostic protocols for each topic, and a critical comparison among them was made, in order to define the gold standard diagnostic method: a) E. histolytica/E. dispar: in vitro culture, zymodeme typization, biomolecular identification (PCR), immunoenzymatic assay (ELISA) for direct detection in stools of specific surface antigenic lectins; b) Acanthamoeba spp.: in vitro culture, light and ultrastructural characterization, species identification by immunofluorescence method with monoclonal antibodies, in vitro pharmacological studies; c) Microsporidia: ultrastructural (TEM), biomolecular (PCR), biochemical and immunological (SDS-PAGE, Immunoblotting) studies for species identification, use of advanced ultrastructural techniques ("freeze-etching", "deep-etching") in order to deepen the spore wall structure, to study the cytoskeletal function of actin and to define the mode of infection, in vitro pharmacological assays on some inhibitors of chitin-synthases.

Acanthamoeba↗
PubMed2000

Genetic identification of neurons controlling a sexually dimorphic behaviour.

In the fruit fly Drosophila melanogaster, locomotor activity is sexually dimorphic: female flies constantly modulate their activity pattern whereas males show a steadier, stereotyped walking pace [1]. Here, we mapped the area of the brain controlling this behavioural dimorphism. Adult male Drosophila expressing a dominant feminising transgene in a small cluster of neurons in the pars intercerebralis exhibited a female-like pattern of locomotor activity. Genetic ablation of these neurons prevented the feminisation of the locomotor activity of transgenic males. The results suggest that this cluster of neurons modulates sex-specific activity, but is not involved in initiating fly locomotion. Nor does it control male courtship behaviour, because feminisation of courtship was not correlated with the feminisation of locomotor activity.

Animals↗
PubMed2000

Calcipotriol treatment of confluent and reticulated papillomatosis (Gougerot-Carteaud syndrome).

Gougerot-Carteaud syndrome or confluent and reticulated papillomatosis (CRP), was first described by Gougerot and Carteaud as dermatosis. It is generally considered a rare condition. The eruption consists confluent, flat, brown papules localized primarily to the intermammary and interscapular regions with subsequent spread to the breast and abdomen; at the periphery, the papules spread out forming a pigmented reticulated pattern. At present, the aetiology of CRP remains unknown. The two prominent theories are an abnormal host response to fungi and a keratinization defect. Other hypothesis include photosensitivity, genetic factor, amyloidosis cutis and endocrinopathy.

Adolescent↗
PubMed2000

Intestinal parasitic infections in an institution for the mentally retarded.

Of 550 mentally retarded patients in an Italian institution, 125 (23%) were found to be infected with intestinal parasites. The infections were most frequent in young men, those with severe mental retardation, the chronically institutionalized and those living in older wards. Ninety-four (75.2%) of the parasitised subjects were infected only with protozoa, 25 (20%) only with helminths, and six (4.8%) with protozoa and helminths. Entamoeba histolytica and E. dispar infections were detected, but at low prevalences; in-vitro culture in Robinson's medium and isoenzyme electrophoresis of the cloned amoebic isolates indicated one infection with E. histolytica (zymodeme XII) and two infections with E. dispar (zymodemes I and III). All three Entamoeba-positive subjects were asymptomatic cyst-passers. Antibodies to E. histolytica were detected in seven (1%) of the sera from the 550 patients examined; only one of these was a carrier of an E. dispar strain at the time of investigation. The low prevalences of all the parasitic infections and of the amoebic infections in particular (compared with those observed previously in institutions for the mentally retarded) reflect relatively good facilities and sanitary conditions, an adequate number of well trained staff and good control of the more susceptible subjects.

Adolescent↗
PubMed2000

In vitro efficacy of nikkomycin Z against the human isolate of the microsporidian species Encephalitozoon hellem.

Since 1985 microsporidia have been recognized as a cause of emerging infections in humans, mainly in immunocompromised human immunodeficiency virus-positive subjects. As chitin is a basic component of the microsporidian infective stage, the spore, we evaluated in vitro the susceptibility of a human-derived strain of Encephalitozoon hellem to nikkomycin Z, a peptide-nucleoside antibiotic known as a competitive inhibitor of chitin synthase enzymes. Transmission electron microscopy showed that this drug, at 25 microgram/ml, reduced the number of parasitic foci by about 35% +/- standard deviation after 7 days of culture (P < 0.0001) and induced cell damage of both mature and immature spores and also other sporogonic and merogonic stages. In particular, an irregular outline of the cell shape and an abnormally condensed cytoplasm in meronts and sporonts were documented. Also, the polar tubule and the polaroplast membranes appeared disarrayed in the sporoblast stage. The spore wall showed an enlarged endospore and delaminated exospore. Mature spores had a complete cytoplasmic disorganization and a swollen and delaminated cell wall. No ultrastructural cell damage was observed in uninfected control cultures treated with the drug.

Aminoglycosides↗
PubMed1999

Fever: links with an ancient receptor.

Recent advances have provided evidence that prostaglandin E2 mediates the generation of fever in response to interleukin-1 or lipopolysaccharide and have reinforced the similarities of signaling downstream of these two pyrogens.

Animals↗
PubMed1999

Neuroprotective effects of Gly-Pro-Glu, the N-terminal tripeptide of IGF-1, in the hippocampus in vitro.

Insulin-like growth factor 1 (IGF-1) plays a critical role in CNS development. IGF-1 can block neuronal apoptosis in vitro and in vivo. IGF-1 is thought to be cleaved into des-N-(1-3)-IGF-1 and an amino terminal glycine-proline-glutamate (GPE tripeptide). Here we report a neuroprotective role for GPE tripeptide, with enhanced survival of the CA1-2 hippocampal neurons following an excitotoxic insult in vitro. Binding and displacement studies suggest uniquely distributed sites of action within the rat including the hippocampal CA1-2, pyriform cortex, amygdala, choroid plexus, blood vessels and to a lesser extent in the cortical regions. A similar pattern of binding was seen in the human. This finding could lead to new strategies to reduce neuronal death after injury and in disease.

Animals↗
PubMed1999

Experimental respiratory cryptosporidiosis in immunosuppressed rats: a light and electron microscopy study.

Cryptosporidium parvum is a coccidian protozoon that causes diarrhoeal enteritis in immunocompetent and immunocompromised humans and other mammals. Sometimes, chiefly in HIV-infected subjects, anatomical sites other than gastro-intestinal tract, such as the biliary and respiratory tree, are involved. We performed an experimental respiratory infection in immunosuppressed albino rats with a C. parvum human-derived isolate, to confirm the possibility of a primary infection at this site and to evaluate the protozoan damages by light and also by transmission electron microscopy (TEM). The animals were infected intratracheally with 1 x 10(6) C. parvum oocysts/ml and, from the 7th day post-infection, biological specimens of trachea, bronchi, lung and ileum were zoopsied. A sole cryptosporidial colonization of the respiratory tract, from the trachea to the median bronchi, without lung parenchyma infection, was observed. Moreover 13/33 (39.4%) rats also developed intestinal infection. TEM study of the respiratory tree specimens demonstrated that cryptosporidia infect either ciliated or goblet cells, and confirmed the role of microvilli in the parasite cell adhesion. The most relevant alterations involved the ciliated cells, with loss of cilia and nuclear and cytoplasmic damages.

Animals↗
PubMed1999

Symptomatic and asymptomatic amoebiasis in two heterosexual couples.

Four cases of amoebiasis are described: two symptomatic with intestinal and hepatic involvement and two asymptomatic, diagnosed in two, heterosexual, Italian couples. Infection was probably acquired first by the men, via an indirect faccal-oral route, and then transmitted to their partners in the same way. The two amoebic strains isolated, from the woman of one couple and the man of the other, were characterized by electrophoresis as zymodemes II alpha- and XIX of Entamoeba histolytica. These four cases emphasise once more the role of cyst-passers in the spread of infection and the importance of biochemical identification of the amoebic isolates, enabling more specific treatment.

Acetamides↗
PubMed1998

Post-hepatitis primary disease does not influence 6-year survival after liver transplantation beyond 1 year.

Orthotopic liver transplantation (OLT) is used as a definitive treatment for end-stage liver disease and prolonged posttransplant survival has already been reported. The incidence of late mortality and graft morbidity is, however, not well defined and the role of primary viral disease in the long-term follow-up results is not clear. Data of posttransplant follow-up in 213 patients, 156 adults and 57 children, who survived at least 1 year were reviewed in order to define causes of graft dysfunction, graft loss and death. In 98 patients, 103 persistent graft dysfunctions were found. Thirty-four grafts were later lost [28 deaths and 6 successful retransplantations (re-OLT)]. The results were reviewed grouping patients according to their age and viral hepatitis status at the time of the transplantation. HBV-positive patients (51) showed 4 re-OLT (1 HBV), 3 liver-related deaths (2 HBV), 24 graft dysfunctions (8 HBV, 5 HCV), and 85.2% 6-year survival (based on 100% survival at 1 year). HCV-positive adults (28) showed 1 re-OLT, 3 HCV-related deaths, 24 graft dysfunctions (19 HCV), and 68.8% 6-year survival. HBV-HCV-positive patients (14) showed no graft loss and death, 10 graft dysfunctions (7 HCV, 1 HBV, 2 HBV-HCV), and 81.8% 6-year survival. HBV-HCV-negative adults (63) showed 3 non-hepatitis-related re-OLT, 5 liver-related deaths (2 HCV), 24 graft dysfunctions (6 HCV, 2 HBV), and 83.1% 6-year survival. HBV-HCV-negative children (49) showed no re-OLT, 1 HCV-related death, 14 graft dysfunctions (3 HCV), and 92.6% 6-year survival. HCV-positive children (8) showed 1 HCV-related re-OLT, 2 HCV-related deaths, 4 graft dysfunctions (3 HCV), and 81.3% 6-year survival. The main cause of graft dysfunction was hepatitis (45 HCV and 13 HBV), followed by technical complications (21), rejection (16), recurrent alcoholism (3), HIV infection (1), and unknown causes (4). In this long-term post-transplant follow-up series, viral hepatitis led to graft dysfunction in 58/103 (56.3%) cases, late graft failure was viral hepatitis-related in 11/ 20 (55%) cases, and, as a total, HCV infection was present in 45/58 (77.5%) cases of viral hepatitis-related graft damage. Looking at the timing of hepatitis-related graft failure, in 70% of cases death occurred after the 5th post-transplant year. In our experience, the occurrence of hepatitis, particularly HCV induced, was common and led to abnormal graft function, but the 6-year post-transplant survival (based on 100% survival at 1 year) in patients surviving for at least 1 year did not differ on the basis of the pretransplant viral hepatitis status. This finding may be consistent with the slow progression of the viral damage and longer follow-up results remain to be established. Nevertheless, data from the present study suggest that in long-term liver transplant survivors, the risk of deteriorating liver damage and eventual failure after 5 years remains only in those patients experiencing a viral hepatitis infection.

Adolescent↗