María José Alonso

Duodenal leishmaniasis diagnosed by biopsy in two HIV-positive patients

We describe two cases of duodenal leishmaniasis in patients with human immunodeficiency virus (HIV) infection, diagnosed by light and electron microscopy. The patients presented nonspecific signs and symptoms, blood cultures were sterile, and serological tests for Leishmania spp. were negative. Endoscopy showed normal-appearing mucosa in one patient and possible peptic duodenitis in the other patient. In these patients, the parasite was only detected in a duodenal biopsy specimen. In view of the unusual location of the parasite and the fact that the diagnostic and dissemination of the disease was established by means of conventional biopsy, this is not a routine procedure for the diagnosis of leishmaniasis because the classic procedures require the demonstration of antibodies and visualization in bone marrow, lymph nodes, liver and/or spleen aspirates. We decided to report these two cases to call attention to the possible finding of Leishmania amastigotes in biopsies from intestinal mucosa in HIV infected patients.

LABELLING PATTERN OBTAINED BY NON‐ISOTOPIC IN SITU HYBRIDIZATION AS A PROGNOSTIC FACTOR IN HPV‐ASSOCIATED LESIONS

In the study of infection of the lower female genital tract caused by human papillomavirus (HPV), one of the main concerns is the search for prognostic factors to predict the evolution of premalignant low‐ and high‐grade squamous intraepithelial lesions. This study has evaluated the prognostic usefulness of the patterns of positive reaction obtained by non‐isotopic in situ hybridization (NISH), referred to as diffuse, punctate, or mixed ‘labelling patterns’. The study examined 141 vulvar and uterine cervical biopsy specimens that were positive for HPV by a NISH screening technique and that had the following histological diagnoses: low‐grade squamous intraepithelial lesion (LSIL; n=87); high‐grade squamous intraepithelial lesion (HSIL, n=40); and squamous cell carcinoma (SCC n=14). Typing of all the specimens was carried out by NISH with DNA probes specific for HPV types 6/11 (low risk), 16/18 (high risk), and 31/33/51 (intermediate risk), and the labelling pattern observed in each specimen was recorded. Statistical analysis of the results showed that there was a significant difference in the distribution of labelling patterns, both by lesion diagnosis (P≤0·004) and by infecting viral type (P≤10−6). Lesions with a punctate or mixed pattern are considered more likely to undergo malignant evolution and consequently have a worse prognosis than lesions with a diffuse pattern.

Evolving architectural patterns in microbial colonies development.

Semithin sections of colonies of three ATCC strains (Staphylococcus aureus, Escherichia coli, and Candida albicans) showed that their internal structure had specific patterns that evolved over the time. These patterns generally were defined by the presence of different layers composed of microorganisms with variable population densities and dead cells. The observed structures in this study could be explained as a particular form of biofilm with an air‐semisolid interface. Microsc. Res. Tech. 2010.