María Atilia Gómez

Human Papillomavirus Is Present in Some Cases of Childhood Penile Lichen Sclerosus: An In Situ Hybridization and SP‐PCR Study

Abstract: Lichen sclerosus (LS) is a skin disease that may affect both sexes at all ages and at any site. Its etiology remains unknown. The observation of focal koilocytotic‐like changes in the stratum malpighii in prepuce samples of LS in children prompted us to investigate the presence of HPV‐DNA. Twenty‐three paraffin‐embedded samples of LS lesions from children aged 4 to 14 years were studied using nested‐PCR and in situ hybridization (ISH). Twelve out of 23 cases amplified HPV‐DNA (8 cases corresponded to HPV‐DNA type 6; 2 cases each to HPV‐DNA types 16 and 18). ISH detected HPV sequences in the nuclei of koilocytotic and some parakeratotic cells in 13 cases (9/13 also HPV‐DNA positive by PCR). Our results demonstrated the presence of HPV‐DNA in roughly 70% of cases of LS of the prepuce in children. We highlight the observation of koilocytotic‐like changes in the prepuce and its association with HPV. The possible pathogenetic significance between the virus and the lesion is not settled.

p53 codon 72 genotypes in HPV infection and cervical disease

OBJECTIVE [corrected] An experimental study has indicated that individuals homozygous for the Arg-encoding allele of p53 gene may have an increased susceptibility to HPV-related cervical cancer but many epidemiological studies have failed to repeat this result. Many epidemiological studies have failed in the attempt to repeat this results. The aim of the present work was to investigate whether the p53 arginine allele confers a risk factor for cervical carcinogenesis. STUDY DESIGN Using PCR based technology, DNAs from 90 normal cervical samples and 205 abnormal cervical tissue scrapes were analyzed for the type of HPV present and p53 codon 72 polymorphism. RESULTS Non statistically significant differences were found for the frequencies of p53 genotypes in the different cytological/histological groups (chi2=1.4; P=0.97) nor for the risk for HPV infection (chi2=1; P=0.9). CONCLUSION This study showed that polymorphism at codon 72 of TP53 gene is not associated with an increased susceptibility to cervical disease and/or HPV infection in the Argentine women population.

Detection of c-erbB-2 Gene Amplification in Cervical Scrapes Positive for Human Papillomavirus (HPV)

c-erbB-2 gene amplification has been described in a variety of human cancers, but it has been poorly studied in noncancerous cytological samples from genital specimens positive for human papillomavirus (HPV). Furthermore, the relationship between this genetic event and the presence of high-risk and low-risk HPV types is poorly studied. Eighty-four noncancerous cytological samples from exocervical specimens that were positive for HPV types 6, 16, and 18 were analyzed for c-erbB-2 gene amplification using the genomic differential polymerase chain reaction with the single copy reference gene. An association between c-erbB-2 gene amplification and the group corresponding to HPV type 6 was found. Within the low-risk HPV group, c-erbB-2 amplification was associated to cervical intraepithelial neoplasia of grade I (CIN I). Because in the samples analyzed, most of the CIN I stage was characterized by a koilocytotic pattern, c-erbB-2 amplification could be related to this kind of cellular alteration. It would be important to study c-erbB-2 gene amplification and also gene expression in different CIN stages in order to determine its role and significance in cervical cancer.

HLA-DQA1 allele typing by nonisotopic PCR-LIS-SSCP

In the present study we used a simple and reliable method for HLA-DQA1 allele typing based on the single-stranded conformation polymorphism (SSCP) properties of DNA molecules obtained by PCR. The technique consists of PCR amplification of a DNA fragment comprising the second exon of the HLA-DQA1 gene, amplicon denaturation using a low ionic strength solution (LIS), and electrophoresis on a small native polyacrylamide gel, followed by a rapid silver staining procedure. In order to validate the technique and to obtain the allele patterns for the DQA1 gene, 50 cervical samples were typed using this methodology and the commercial Amplitype HLA DQA1 Amplification and Typing kit. All the alleles detected with the kit were characterized by the LIS-SSCP approach. This procedure proved to be useful for population screening and typing of the DQA1 gene as well as for detecting new alleles or mutations in the donor-recipient molecular matching of HLA class II genes.

Allele frequencies of 15 STR loci in the population of the city of Quito, Ecuador.

Quito City Population (Ecuador, South America, n = 116–207).

Whose Small Bowel Biopsy Is This? Aids from Molecular Biology: Use of Molecular Techniques for Mismatched Specimen Identification

Accurate and correct identification is of paramount importance when processing biopsies in pathology laboratories. Although extreme care is dedicated to reducing human error in this process, such error is sometimes unavoidable and, occasionally, mislabeling occurs. This may result in harm to the patient not only due to errors in diagnosis but also to the resulting treatment, which may be inappropriate. We report here an episode of mismatched small bowel biopsies that happened in our laboratory, and the way in which it was solved through PCR technique investigation. The procedure allowed a rapid and accurate identification of the samples, avoiding any harm to the patients involved. The first patient was a 2-year-old boy who presented with chronic diarrhea (which he had had since 6 months of age), undernourishment (11.7 kg), and abdominal swelling. There were no familial data of celiac disease. The mother noted that when she stopped feeding the child with flour-containing foods for 1 wk, improvement in the stools resulted. The child’s diet had included wheat flour since the age of 5 months. The second patient was a 5-year-old boy who presented with lower abdominal distention and weight in the 50th percentile (16,250 kg). Serology for endomisial antibodies was positive. Both patients were submitted to peroral small bowel biopsy for villous atrophy, which at this age represents celiac disease in the vast majority of the cases. Samples were received at the pathology laboratory the same day. Mistakenly, the samples were given the same identification number. The problem arose at the time of microscopic reading, since both slides with the same number presented different microscopic features. One showed complete villous atrophy (villous/crypt ratio: 0.5, or enteropathy grade 4), while the other had a normal villous crypt ratio ( 2.5).