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.

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.

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.

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.

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.

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.

Biotechnologies and acute hepatic failure

Orthotopic liver transplantation survival for patients with acute liver failure is poor (50%). Mortality on the waiting list is high due to the lack of donors. For these reasons, the possibility of sustaining hepatic function by extra-corporeal liver perfusion must be considered. In this experimental research, two groups of pigs have been submitted to total de-vascularisation of the liver causing acute hepatic failure. In the first group (4 pigs) no extra-corporeal assistance has been used after total de-vascularisation. All pigs died between 16 and 33 hours after the acute hepatic failure was induced. In the second group (8 pigs) after complete hepatic de-vascularisation an extra-corporeal hepatic support by continuous allo-perfusion of isolated liver was performed using the Abouna-Costa extra-corporeal circuit. All pigs were observed during the acute hepatic failure which lasted from 6.30 to 7.30 hours. The data that were more positively influenced by the extra-corporeal assistance were ammonia and lactates that improved after the application of hepatic assistance.

Evidence of actin in the cytoskeleton of microsporidia

Using transmission electron microscopy, immuno-electron microscopy, and biochemical techniques such as 2-D electrophoresis and immunoblotting, actin was found in all biological stages of the microsporidia Encephalitozoon hellem and Encephalitozoon cuniculi.

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.

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.

Evidence that SMS 201-995 enhances the immunosuppressive effect of FK506

Somatostatin (SS) was originally described as a growth hormone release inhibiting factor synthesised in the hypothalamus. Recently, SS and its receptor (SSTR) have been demonstrated in lymphoid tissues and seem to play a regulatory, largely inhibitory, role in immune responses. The aim of the present study was to check the immunosuppressive effect of a SS derived peptide, the octreotide (SMS 201-995) and to verify whether this molecule acted synergistically with FK506. An immunosuppressive effect of SMS was observed on the proliferation of rat spleen cells induced in vitro, either by polyclonal mitogens such as PHA or by alloantigens. With PHA stimulation, 10(-14) M SMS significantly enhanced the immunosuppressive action of 0.00001 microg/ml FK506. The addition of SMS in MLR (10(-11)-10(-9)M) increased the antiproliferative effect of both 0.0001 microg/ml and 0.00001 microg/ml FK506. In consideration of the extremely low concentration of both drugs that was required to obtain a good immunosuppression in vitro, we verified the association of FK506 and SMS in vivo in an allogeneic skin graft model that used Lewis (Lew) rats as donors and Brown Norway (BN) rats as recipients. BN treated with 0.1 mg/kg FK506 and 0.5-10 microg/kg SMS showed a significant increase in mean skin allograft survival time when compared to either a monotherapy or control group. None of the animals died or showed signs of drug-related toxicity. In conclusion, a combined therapy of SMS and FK506, administered at lower dosages than those that are considered therapeutic, led to an effective immunosuppression without any undesirable side effects.

In vitro effectiveness of povidone-iodine on Acanthamoeba isolates from human cornea

Acanthamoeba keratitis is a severe ocular infection secondary to accidental macro- or microscopic trauma of the cornea. Starting in 1985, a dramatic increase of this infection was recorded along with the spread of contact lens use. This protozoal disease is difficult to treat because of the scarcity of efficacious topical and systemic drugs. We evaluated the in vitro effectiveness of povidone-iodine (PVP-I [Betadine]), an agent with broad antibacterial and antiviral activity, compared to that of chlorhexidine (CXD), a cationic antiseptic, on Acanthamoeba isolates from patients with amebic keratitis. The results showed that PVP-I solution from 0.5 to 2.5% has a better antiamebic activity both on trophic and cystic stages of Acanthamoeba spp. than does CXD.