Sergio Andrés Tonon

Physical status of the E2 human papilloma virus 16 viral gene in cervical preneoplastic and neoplastic lesions

BACKGROUND Integration of human papilloma virus (HPV) 16 DNA is considered an important genetic change in cervical lesion progression towards ICC. The viral E2 gene is often disrupted by this process, releasing suppression of viral E6/E7 oncogenes, a key factor for oncogenic progression. OBJECTIVES To evaluate the physical status of HPV 16 E2 gene in cervical preneoplastic and neoplastic lesions and its relation with lesion severity. STUDY DESIGN A sensitive PCR approach for the detection of an intact E2 HPV 16 gene in infected epithelial cells from the cervix with low grade squamous intraepithelial lesion (LGSIL), high grade squamous intraepithelial lesion (HGSIL) and invasive cervical carcinoma (ICC) diagnosis was applied. The correlation between gene disruption and lesion stage was examined. RESULTS Sixty-two LGSIL, 39 HGSIL and 24 ICC samples were analyzed. Fifty-seven LGSIL [92%], 13 HGSIL [33%] and 4 ICC [17%] showed results compatible with an intact E2 gene, while 5 LGSIL [8%], 26 HGSIL [67%] and 20 ICC [83%] samples gave no signal. CONCLUSIONS HPV 16 E2 gene disruption showed a positive correlation with cervical lesion progression, particularly from LGSIL to HGSIL. Although additional genetic events are very likely to be needed for HGSIL to ICC progression, the E2 gene disruption is a putative early marker to consider in the prognostic analysis of HPV 16 chronically infected women.

Mycoflora of paddy and milled rice produced in the region of Northeastern Argentina and Southern Paraguay

Thirty samples of paddy rice and twenty-five of milled rice were obtained from processing centers located in two northern Provinces of Argentina and one southern Province of Paraguay. Contaminating fungi were enumerated by direct plating on dichloran rose bengal chloramphenicol agar and oxytetracycline glucose yeast extract agar before and after surface disinfection. All fungi were isolated and identified to the genus level and percentage infection of samples calculated. Those belonging to the genera Penicillium, Aspergillus and Fusarium were identified to species level. The surface mycoflora was dominated by storage fungi, notably Penicillium citrinum (73% of samples), P. islandicum (60% of samples), Aspergillus niger, A. flavus and Fusarium semitectum. The major fungi found as internal contaminants of paddy rice were, again, Penicillium citrinum (66% of samples) and P. islandicum (50% of samples). Milled rice showed a lower level of contamination, but with a similar species distribution, Penicillium citrinum and P. islandicum again being the main contaminants. The presence of these species suggests a potential for mycotoxin production. Further studies are needed to establish the mycotoxin quality of rice from this region.

Human Papillomavirus Cervical Infection and Associated Risk Factors in a Region of Argentina With a High Incidence of Cervical Carcinoma

OBJECTIVE: To assess the prevalence and potential risk factors associated with human papillomavirus (HPV) cervical infection among women residing in a region of northeastern Argentina with a high incidence of cervical cancer. METHODS: A case-control study of 330 women participating in a cervical cytological screening program conducted in Posadas city, Misiones, Argentina, from February 1997 to November 1998 was carried out. Standardized questionnaires were administered, and clinical examination including colposcopy was performed. Fresh endocervical specimens for HPV DNA detection by generic polymerase chain reaction were collected and the products typed by dot-blot hybridization. RESULTS: Human papillomavirus DNA was found in 61% of samples analyzed (185/301). Samples with normal cytology had a 43% infection rate (85/199), while those classified as low-grade squamous intraepithelial lesion, high-grade squamous intraepithelial lesion, and invasive cervical carcinoma had an infection rate of 96% (53/55), 100% (29/29), and 100% (18/18), respectively. Human papillomavirus typing showed a 64% (118/185) prevalence of type 16 among all the infected population analyzed; type 16 was detected among 49% (42/85) of infected samples with normal cytology and in an average of 74% (74/100) with abnormal cytology. Sexual behavior, residence in southern Paraguay, and history of a previous sexually transmitted diseases were the main risk factors associated with high-grade cervical lesions. CONCLUSIONS: An elevated prevalence of HPV infection was detected in this population, which also has a high incidence of cervical cancer. The broad distribution of high-risk HPV type 16 in women with normal cytology and colposcopy suggests that viral infection is an important determinant of regional cancer incidence.