Phaeohyphomycosis of the nasal sinuses caused by a new species of Exserohilum.

A 27-year-old man with a 6-year history of allergies developed nasal polyps that occluded his nose and prevented visual examination beyond the nasal vestibules. Histological examination of the polyps and bony tissue revealed septate, dematiaceous hyphae invading the bone trabeculae. A dematiaceous fungus was isolated in pure culture from the diseased tissue. Detailed mycological examination of the isolate showed that it produced numerous, distinctive poroconidia from erect, geniculate, sympodial conidiophores. The conidia were straight and cylindroellipsoidal, had 8 to 13 distosepta, and had protruding hila. The outer cell walls of the conidia, which were initially smooth, became unevenly roughened on aging. Comparison with other Exserohilum species revealed that the isolate represented an undescribed species; it is named Exserohilum mcginnisii sp. nov.     

Zygomycosis. Report of four cases with formation of chlamydoconidia in tissue

The authors describe spheric to ovoid chlamydoconidia and mucoraceous hyphae in tissues from four patients, two with cutaneous and two with pulmonary zygomycosis. The diagnosis in each case was confirmed by immunofluorescence staining and the presence of characteristic hyphae in tissue. It is important that these conidia be recognized, because they can easily be mistaken for other fungi, nematode ova, or other microorganisms in tissue sections, thereby resulting in the potential for misdiagnosis.     

Pythium insidiosum sp. nov., the etiologic agent of pythiosis.

Pythium insidiosum sp. nov., the etiologic agent of pythiosis, a cosmopolitan disease of horses, cattle, and dogs, is described and illustrated.     

Increased expression of periplasmic Cu,Zn superoxide dismutase enhances survival of Escherichia coli invasive strains within nonphagocytic cells

We have studied the influence of periplasmic Cu,Zn superoxide dismutase on the intracellular survival of Escherichia coli strains able to invade epithelial cells by the expression of the inv gene from Yersinia pseudotuberculosis but unable to multiply intracellularly. Intracellular viability assays, confirmed by electron microscopy observations, showed that invasive strains of E. coli engineered to increase Cu,Zn superoxide dismutase production are much more resistant to intracellular killing than strains containing only the chromosomal sodC copy. However, we have found only a slight difference in survival within HeLa cells between a sodC-null mutant and its isogenic wild-type strain. Such a small difference in survival correlates with the very low expression of this enzyme in the wild-type strain. We have also observed that acid- and oxidative stress-sensitive E. coli HB101(pRI203) is more rapidly killed in epithelial cells than E. coli GC4468(pRI203). The high mortality of E. coli HB101(pRI203), independent of the acidification of the endosome, is abolished by the overexpression of sodC. Our data suggest that oxyradicals are involved in the mechanisms of bacterial killing within epithelial cells and that high-level production of periplasmic Cu,Zn superoxide dismutase provides bacteria with an effective protection against oxidative damage. We propose that Cu,Zn superoxide dismutase could offer an important selective advantage in survival within host cells to bacteria expressing high levels of this enzyme.     

Efficacy of interferon treatment (IFN) in elderly patients with chronic hepatitis C

The aim of this study was to evaluate the efficacy and tolerability of interferon treatment in aged patients with chronic hepatitis C. One hundred and fifty-four patients with chronic hepatitis C, consecutively treated with a-interferon (a-IFN), were retrospectively subdivided into two groups according to age =60 or <60 years. The two groups were compared in terms of biochemical and histological activity of the disease, HCV genotype, total dose of IFN received, incidence of side effects and rate of response to treatment. Statistical analysis was performed by Student's t test, chi-square test and Fisher's exact test. Aged patients had a higher prevalence of HCV genotype 1b and cirrhosis and received a lower dose of the drug. No differences were found in other epidemiological-clinical characteristics before treatment. The rate of sustained response and long-term response to therapy was similar in the two groups of patients (18% and 8% in the aged and 20% and 13% in the younger respectively). There was a trend of more frequent major side effects in aged patients (p=0.07). Treatment of chronic hepatitis C with a-IFN had the same efficacy in the two groups observed. In aged patients with chronic hepatitis C treatment with the more effective pegylated IFN should be taken into consideration, especially when association with ribavirin is at high risk of adverse events.     

Transitory subependymal cysts in the developing rat rhombencephalon

Summary A bilaterally symmetrical cystic cavity is situated in the subependymal neuropil of the rostral rhombencephalon of the rat during the perinatal period of ontogeny. These cysts are formed by the confluence of enlarged extracellular spaces in this region between E18 and E20. The cysts are present for about 2 weeks but disappear on about P15 without trace. They have a maximal volume of about 0.004 to 0.006 mm³ on P2, with a rostrocaudal extension of about 200 m. Their shape is characterized by a medial convexity and a lateral concavity, and they have their maximal circumference at about the middle of the rostrocaudal axis. The caudal portion is juxtaposed to the subependyma, while the rostral part lies in the neuropil of the presumptive griseum centrale pontis. In the lumen and the wall of the cysts are found numerous macrophages, hlioblasts and some degenerating axons and dendrites.The significance of these cysts in the context of morphogenesis and the origin of the numerous macrophages within them are both unresolved.     

Imported paracoccidioidomycosis : A public health problem in non-endemic areas

Diagnosis of paracoccidioidomycosis in an immigrant who had returned to Italy following a long sojourn in Venezuela prompted a review of imported cases of this Latin American disease in nonendemic countries. Forty-two such instances of well documented paracoccidioidomycosis were compiled. Among these, eleven individuals had arrived in nonendemic countries with active symptomatic infections, fifteen others were first suspected of having tuberculosis, and four each were considered to have blastomycosis caused by Blastomyces dermatidis and carcinomas. Three, individuals were considered to have Wegner's granulomatosis or blastomycosis. Two other patients were treated for syphilis before being diagnosed as having paracocidioidomycosis. A striking feature of most of these cases was the long asymptomatic period following initial infection. The dormant periods ranged form four months to 60 years with an average duration of 14 years. The need to question patients about travel to or residency in foreign countries is emphasized, along with the necessity to include the mycoses in differential diagnoses. Three reported cases, all from Africa with no history of travel to the endemic areas of the New World, were considered to be doubtful. In one of these, Russell bodies apparently had been mistaken for the tissue-form cells of Paracoccidioides brasiliensis. A Japanese case, upon restudy of available histologic slides, revealed that the fungal cells present in various organs were those of Cryptococcus neoformans and not of P. brasiliensis.Corresponding author