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L L Villa

Publications and source records attributed to L L Villa.

At least 37 records · Page 2Linked to original sources
PubMed2000

A cumulative case-control study of risk factor profiles for oncogenic and nononcogenic cervical human papillomavirus infections.

Human papillomaviruses (HPVs) play an essential role in the etiology of cervical cancer, but besides an established role for sexual transmission, little is known about other risk factors for HPV infection. Risk factors for nononcogenic, oncogenic, and HPV 16 cervical infections were investigated using a cumulative case-control approach nested in an ongoing cohort study of low income women from São Paulo, Brazil. HPV DNA was detected and typed by the MY09/11 PCR protocol. Risk factor information was obtained via interviews. In a case-control analysis, we compared women who harbored infections with exclusively nononcogenic types (n = 123), exclusively oncogenic types (n = 94), and any HPV 16 (n = 60) to women remaining HPV-negative (n = 512) throughout 1 year of follow-up. A strong negative association was found between age and oncogenic infections, but not with nononcogenic infections. Oral contraceptive use was strongly and exclusively associated with oncogenic and HPV 16 infections. Markers of sexual activity were associated with all types of infections, although with varying strengths. Our results suggest some important differences in the epidemiological correlates of HPV infection according to oncogenicity that may have implications for the-planning of specific preventive strategies aiming at reduction of cervical cancer risk.

Adolescent↗
PubMed2000

Major histocompatibility complex class II polymorphisms and risk of cervical cancer and human papillomavirus infection in Brazilian women.

Infection with high-risk human papillomavirus (HPV) is the major risk factor for the development of malignant lesions in the uterine cervix. Environmental, behavioral, and ill-defined genetic factors also have been implicated in the pathogenesis of this disease. Associations between human leukocyte antigens (HLAs) and cervical cancer, precursor lesions, and HPV infections have been reported in several populations. To verify whether HLA-DRB1, -DQA1, and -DQB1 diversity is related to cervical cancer in the Brazilian population, 161 cases and 257 controls were HLA typed. Variants of DQA1 and DQB1 promoter regions were also typed in 92 cases and 228 controls. Polymorphism in HLA genes and promoters was distinguished by PCR-based methods, and the magnitude of associations was determined by logistic regression analysis. DRB1*15 [confounder-adjusted odds ratio (OR), 2.24; 95% confidence interval (CI), 1.29-3.90], DRB1*1503 (OR, 2.52; 95% CI, 1.16-5.48), and haplotype DRB1*15-DQB1*0602 (OR, 2.04; 95% CI, 1.15-3.61) were positively associated with cervical cancer. When we considered only DR15 haplotypes that did not carry the DQB1*0602 allele, the risk attributed to DRB1*15 more than doubled. A negative association was found between DQB1*05 and cervical cancer (OR, 0.57; 95% CI, 0.35-0.92), and similar trends were observed for DQA1*0101/04, DRB1*0101, and DRB1*1302. HPV positivity among controls was associated with DRB1*1503 (OR, 4.60; 95% CI, 1.33-15.9), DRB1*0405 (OR, 6.21; 95% CI, 1.66-23.2), and DQB1*0602 (OR, 2.48; 95% CI, 1.06-5.80). We suggest that HLA class II polymorphisms are involved in genetic susceptibility to cervical cancer and HPV infection in a Brazilian population from an area with a high incidence of this neoplasia.

Adolescent↗
PubMed1999

Squamous cell carcinoma of the vulva in Brazil: prognostic importance of host and viral variables.

BACKGROUND: Certain clinicopathologic features of vulvar squamous cell carcinoma have been correlated with adverse prognosis. However, few large-scale studies have addressed their role in patient survival. This study examined the relationship between multiple variables and prognosis in a large group of vulvar cancers in Brazil. METHODS: One hundred eighty-four Brazilian women with vulvar carcinoma were studied and the following variables recorded: age, pathologic TNM stage, survival, histologic grade, tumor histologic pattern, invasion pattern, tumor thickness, and tissue stromal and inflammatory response. Human papillomavirus (HPV) was detected by polymerase chain reaction amplification of extracted archival DNA. Data were analyzed using Cox proportional hazards modeling. RESULTS: After controlling for age, the probability of cancer survival decreased with increasing age, stage, grade, and tumor thickness, a fibromyxoid stromal response, infiltrative growth pattern, and basaloid histologic pattern. With the exception of fibromyxoid stromal response, each of these variables remained prognostically significant after adjustment for several other predictors in a multivariate model. Women whose tumors displayed a basaloid pattern were 3.5 times as likely to die from cancer than those with keratinizing tumors [hazard ratio (HR) = 3.5, 95% CI(1.3-9.2)]. An infiltrative invasion pattern strongly increased the probability of cancer death [HR = 4.6, 95% CI(1.9,11.4)]. HPV status did not influence survival, despite its association with basaloid histology. CONCLUSIONS: Previously reported associations of negative HPV status and fibromyxoid response with adverse prognosis in vulvar cancer were not confirmed by multivariate analysis. Basaloid variants, and particularly diffusely infiltrative tumors, carry an adverse prognosis.

Adult↗
PubMed1999

A novel, internally competitive polymerase chain reaction for quantification of human cytomegalovirus DNA in human leukocytes.

The rapid, low cost estimation of Human Cytomegalovirus (HCMV) viral load in the blood of immunosupressed individuals is crucial for the timely diagnosis of transplant recipients with clinically significant HCMV infections requiring treatment. To this end we have developed a novel polymerase chain reaction (PCR) assay with internal controls for competitive quantification of cytomegalovirus DNA in human leukocytes. The reaction simultaneously amplifies, under reduced stringency conditions, a 136 bp fragment of the HCMV LA gene together with a single anonymous 200 bp fragment of human DNA using a single-primer pair. The primers used are specific for the HCMV gene sequence but contain a single mismatch that permits the amplification of the competing human DNA fragment. Quantification is achieved by comparison of the amount of the two products. The assay quantifies between 10(3)and 10(6)HCMV genomes in 10(6)leukocytes, a range that permits low-level clinically unimportant HCMV infections to be distinguished from those likely to cause serious disease. The advantages of the method are that no external controls are needed, quantification is achieved from a single reaction and no separate measurement of host DNA concentration is required.

Binding, Competitive↗
PubMed1999

Allelic loss in human papillomavirus-positive and -negative vulvar squamous cell carcinomas.

Vulvar squamous cell carcinoma (VSCC) is a biologically and morphologically diverse disease, consisting of human papillomavirus (HPV)-positive and -negative tumors that differ in their morphological phenotypes and associated vulvar mucosal disorders. This study analyzed the frequencies of allelic loss (loss of heterozygosity (LOH)) in HPV-positive and -negative VSCCs to identify potential targets for the study of preinvasive diseases, to determine whether HPV status influenced patterns of LOH, and to determine whether these patterns differed from HPV-positive tumors of another genital site, cervical squamous cell carcinomas (CSCC). DNA extracted from microdissected archival sections of two index tumors, one each HPV negative and positive, was analyzed for LOH at 65 chromosomal loci. Loci scoring positive with either sample were included in an analysis of 14 additional cases that were also typed for HPV. Frequencies of LOH at loci were computed in a panel of HPV-positive and -negative VSCCs. Twenty-nine loci demonstrated LOH on the initial screen and were used to screen the remaining 14 tumors. High frequencies of LOH were identified, some of which were similar to a prior karyotypic study (3p, 5q, 8p, 10q, 15q, 18q, and 22q) and others of which had not previously been described in VSCC (1q, 2q, 8q, 10p, 11p, 11q, 17p, and 21q). With the exception of 5q and 10p, there were no significant associations between frequency of LOH and HPV status in VSCC. LOH at 3p and 11q were frequent in both VSCC and CSCC; however, allelic losses at several sites, including 5q, 8q, 17p, 21q, and 22q, were much more common in VSCC. VSCCs exhibit a broad range of allelic losses irrespective of HPV status, with high frequencies of LOH on certain chromosomal arms. This suggests that despite their differences in pathogenesis, both HPV-positive and -negative VSCCs share similarities in type and range of genetic losses during their evolution. Whether the different frequencies of LOH observed between VSCC and CSCC are real or reflect differences in stage and/or tumor size remains to be determined by further comparisons. The role of these altered genetic loci in the genesis of preinvasive vulvar mucosal lesions merits additional study.

Carcinoma, Squamous Cell↗
PubMed1999

Epidemiology of acquisition and clearance of cervical human papillomavirus infection in women from a high-risk area for cervical cancer.

Acquisition and clearance of cervical human papillomavirus (HPV) infection were analyzed among 1425 low-income women attending a maternal and child health program in São Paulo, Brazil. Specimens collected every 4 months were tested by a polymerase chain reaction protocol (MY09/11). In all, 357 subjects were positive at least once. There were 1.3% new infections per month, with 38% cumulative positivity after 18 months. Of 177 positive subjects at enrollment, only 35% remained infected after 12 months. The monthly clearance rate was higher for nononcogenic types (12.2%; 95% confidence interval [CI], 9.6-15.4) than for oncogenic HPV infections (9.5%; 95% CI, 7.5-11.9). Median retention times were 8.1 months (95% CI, 7.8-8.3) for oncogenic types and 4.8 months (95% CI, 3.9-5.6) for nononcogenic HPV infections. The mean infection durations were 8.2 and 13.5 months for nononcogenic and oncogenic types, respectively. Although a woman's age did not affect mean duration for oncogenic types (13-14 months), nononcogenic-type infections lasted longer (10. 2 months) among younger (<35 years old) than in older women (5.6 months).

Adult↗
PubMed1999

Relationship between human papillomavirus (HPV) genotyping and genital neoplasia in HIV-positive patients of Santos City, São Paulo, Brazil.

Among HIV-positive women, infection with multiple human papillomavirus (HPV) types is known to be more frequent and persistent, as well as a greater prevalence of high-grade genital lesions. This study aims to characterize, for the first time in Brazil, HPV presence and types among HIV-positive women of a high-risk population for genital intraepithelial neoplasia (GIN) development. A non-anonymous, voluntary, cross-sectional epidemiological survey was conducted, from June 1996 to April 1997, among 141 HIV-positive women followed at the Center of Reference in AIDS (CRAIDS). They were submitted to gynaecological examination, cytological screening and biopsies whenever necessary, for GIN and HPV DNA detection through polymerase chain reaction (PCR) technique. Positive HPV DNA were found in 80.8% patients. Two or more HPV types were detected in 45% of the samples. The most frequent HPV types detected were 16, 18 (30.5%); 61, 53 (24.4%), and non-identified types (18.7%). According to the oncogenic potential, 34.8% were considered of high-risk types. Among these HIV-positive patients, a great variety of HPV types, including high-risk types, was found in anogenital environment, as well as among young women, a great prevalence of high-grade genital lesions. Thus, it should strengthen the need for a periodical careful gynaecological examination among those women.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Detection of point mutations by non-isotopic single strand conformation polymorphism.

We have developed a procedure for nonradioactive single strand conformation polymorphism analysis and applied it to the detection of point mutations in the human tumor suppressor gene p53. The protocol does not require any particular facilities or equipment, such as radioactive handling, large gel units for sequencing, or a semiautomated electrophoresis system. This technique consists of amplification of DNA fragments by PCR with specific oligonucleotide primers, denaturation, and electrophoresis on small neutral polyacrylamide gels, followed by silver staining. The sensitivity of this procedure is comparable to other described techniques and the method is easy to perform and applicable to a variety of tissue specimens.

Female↗
PubMed1999

Genetic susceptibility to HPV infection and cervical cancer.

Squamous cell carcinoma of the cervix (SCCC) is one of the leading causes of death in developing countries. Infection with high-risk human papillomavirus (HPV) is the major risk factor to develop malignant lesions in the cervix. Polymorphisms of the MHC and p53 genes seem to influence the outcome of HPV infection and progression to SCCC, although controversial data have been reported. MHC are highly polymorphic genes that encode molecules involved in antigen presentation, playing a key role in immune regulation, while p53 is a tumor suppressor gene that regulates cell proliferation. The HPV E6 protein from high-risk types binds p53 and mediates its degradation by the ubiquitin pathway. The role of these polymorphisms in genetic susceptibility to HPV infection and to SCCC remains under investigation.

Carcinoma, Squamous Cell↗
PubMed1999

Monitoring human cytomegalovirus viral load in peripheral blood leukocytes of renal transplant recipients by a simple limiting dilution-PCR assay.

To assess the clinical relevance of a semi-quantitative measurement of human cytomegalovirus (HCMV) DNA in renal transplant recipients within the typical clinical context of a developing country where virtually 100% of both receptors and donors are seropositive for this virus, we have undertaken HCMV DNA quantification using a simple, semi-quantitative, limiting dilution polymerase chain reaction (PCR). We evaluated this assay prospectively in 52 renal transplant patients from whom a total of 495 serial blood samples were collected. The samples scored HCMV positive by qualitative PCR had the levels of HCMV DNA determined by end-point dilution-PCR. All patients were HCMV DNA positive during the monitoring period and a diagnosis of symptomatic infection was made for 4 of 52 patients. In symptomatic patients the geometric mean of the highest level of HCMV DNAemia was 152,000 copies per 10(6) leukocytes, while for the asymptomatic group this value was 12,050. Symptomatic patients showed high, protracted HCMV DNA levels, whereas asymptomatic patients demonstrated intermittent low or moderate levels. Using a cut-off value of 100,000 copies per 10(6) leukocytes, the limiting dilution assay had sensitivity of 100%, specificity of 92%, a positive predictive value of 43% and a negative predictive value of 100% for HCMV disease. In this patient group, there was universal HCMV infection but relatively infrequent symptomatic HCMV disease. The two patient groups were readily distinguished by monitoring with the limiting dilution assay, an extremely simple technology immediately applicable in any clinical laboratory with PCR capability.

Antibodies, Viral↗
PubMed1998

Low prevalence of human papillomavirus in a geographic region with a high incidence of head and neck cancer.

BACKGROUND: The main purpose of this study was to determine the prevalence of human papillomavirus (HPV) infection in patients with head and neck carcinomas from Brazil. MATERIALS AND METHODS: Forty-five patients with head and neck squamous cell carcinoma were included in the study, from 1995 to 1996. Forty-two were male and 3 female, with age ranging from 32 to 82 years (median 61). Five patients (11%) did not have previous history of use of tobacco and 38 (90.5%) were heavy smokers. Tumor sites were pyriform sinus, 10; tongue, 11 (oral, 6; base, 5); larynx, 7; floor of mouth, 3; tonsil, 6; retromolar area, 3; inferior gingiva 2; buccal mucosa, 2; and maxillary sinus in 1 patient. Twenty-five were stage IV, 17 stage III, and 3 stage II. RESULTS: The presence of HPV DNA was detected in 5 of 45 patients (11%), all of them with HPV 16. Two patients had HPV DNA in normal mucosa and tumor tissue, 1 patient had HPV DNA only in the normal mucosa and tumor tissue, 1 patient had HPV DNA only in the normal mucosa, and 2 patients were positive for HPV DNA in tumor tissue. Four patients were male and 1 was female; 2 patients were nonsmokers. Three patients had tonsil carcinoma, 1 patient had a tongue carcinoma, and 1 patient had a pyriform sinus cancer. CONCLUSIONS: The role of chemical carcinogens seems to be more important in the genesis of head and neck cancer than is HPV infection. The presence of HPV DNA in 5 of 45 patients stimulates further investigation to determine the role of HPV as a risk factor for head and neck carcinoma.

Adult↗
PubMed1998

A spin cartridge system for DNA extraction from paraffin wax embedded tissues.

A simple and efficient method of DNA extraction from paraffin wax embedded tissues using a spin cartridge system is described. Such DNAs were shown to be suitable for amplification by the polymerase chain reaction, which targeted two human papillomavirus genes and one globin fragment giving rise to products of 450, 150, and 110 base pairs, respectively. Different human tissues, stored for up to 20 years, were successfully amplified, demonstrating the usefulness of this very simple procedure for retrospective studies.

Centrifugation↗
PubMed1997

Human papillomaviruses and cervical cancer.

Molecular and epidemiological studies conducted over the last 20 years led to the recognition of certain types of human papillomavirus (HPV) as the etiological agents of cervical cancer, a very common neoplasia, particularly in developing countries. More than 70 HPVs have been described, including both cutaneous and mucosal types. About half of the known HPVs, and an even higher number of variants, have been isolated from genital mucosas. The association of certain types primarily with normal tissues and benign lesions, as opposed to cancer-associated types, has led to the concept of low and high oncogenic risk HPVs, respectively. The latter express oncogenic proteins that interfere with cell growth control functions. As a consequence of the continuous expression of these viral genomes, chromosome instability may occur, leading to fully transformed cells. Studies indicate that persistence of high-risk HPVs may determine progression to more severe stages of cervical disease, while the majority of HPV infections are transient and do not seem to be important in cervical carcinogenesis. The risk for disease progression seems also to be associated with viral burden. Prospective epidemiological studies will contribute to the knowledge of the natural history of HPV infections and provide information on the determinants of viral persistence. Data derived from these studies may define the clinical utility of HPV testing and its use in cervical cancer prevention programs.

DNA, Viral↗
PubMed1997

Highly sensitive single-step PCR protocol for diagnosis and monitoring of human cytomegalovirus infection in renal transplant recipients.

A multiplex, single-step PCR protocol for the detection of human cytomegalovirus (HCMV) DNA is described. The protocol amplifies regions of the viral LA and IE genes and employs elevated temperatures for both reagent mixing and primer annealing together with product detection by silver staining on polyacrylamide gels. This assay detects one to five HCMV genomes in clinical samples containing up to 100 ng of human DNA, a level of sensitivity equivalent to that of more complex assays involving either nested PCR or postamplification hybridization. As well as being of importance in clinical situations where high-sensitivity qualitative diagnosis is required, this assay is also applicable to the monitoring of HCMV infection in renal transplant recipients. Due to its multiplex format the assay provides quantitative information, in that samples from which a single target is amplified contain on average sevenfold fewer viral genomes per 10(6) leukocytes than those from which both targets are amplified. When weekly blood leukocyte DNA preparations from renal transplant patients were assayed, findings of three consecutive tests in which both HCMV targets were amplified were highly indicative of patients who had developed very high loads of HCMV (100% sensitivity, 88% specificity). We thus show that the same simple PCR assay which permits highly sensitive HCMV diagnosis can also be used for the efficient identification of transplant recipients at risk of clinically significant infection.

Base Sequence↗
PubMed1996

Tumor necrosis factor alpha interferes with the cell cycle of normal and papillomavirus-immortalized human keratinocytes.

We have shown that normal and human papillomavirus (HPV) type 16 immortalized human foreskin keratinocytes are growth inhibited by tumor necrosis factor alpha (TNF-alpha), whereas HPV-18- and SV40-immortalized keratinocytes are resistant to this cytokine (1). In this report, we investigated the expression of mitotic regulatory proteins, such as cyclin A, cyclin B, and p34cdc2. After exposure to TNF-alpha, normal and HPV-16-immortalized cells exhibited a dramatic decrease in the expression of these proteins. In contrast, no alteration in the levels of these proteins was observed after treatment of the resistant cell lines, as well as two HPV-positive cervical carcinoma cell lines. Expression of cyclin E does not seem to be modulated by TNF-alpha in any of the cells tested. On the other hand, cyclin D1, expression is slightly increased in normal keratinocytes and in the HPV-16-immortalized cells, whereas no alteration was observed in the HPV-18-transfected cells. The phosphorylation state of pRb correlated with cell growth; sensitive cells, which accumulate in G0-G1, after exposure to TNF-alpha, exhibited an accumulation of hypophosphorylated pRb, whereas no effect on pRb phosphorylation was observed for HPV-18-immortalized cells. These results clearly correlate with TNF-alpha-induced growth arrest in G0-G1.

CDC2 Protein Kinase↗