Reported changes in sexual behaviour and human papillomavirus knowledge in Peruvian female sex workers following participation in a human papillomavirus vaccine trial.

Limited data exist on the effect of clinical trial participation on sexual behavioural change. Two hundred female sex workers working in Lima, Peru received human papillomavirus (HPV) vaccine in either the standard (0, 2, 6 months) or modified (0, 3, 6 months) schedule. Participants received comprehensive screening and treatment for sexually transmitted infections (STIs), counselling on safe sex practices, education about HPV and the HPV vaccine, contraceptives (oral and condoms) and family planning at each visit. We assessed vaccine completion rates, change in sexual practices, and changes in HPV knowledge before and after participation in the vaccine trial. There were high rates of vaccine completion, 91% overall. The estimated number of reported new and total clients over a 30-day period decreased significantly (P < 0.001). Knowledge about HPV and HPV-related disease increased among all participants. In addition, all participants listed at least one preventive strategy during the month 7 follow-up survey.

Human papillomavirus prevalence, cervical abnormalities and risk factors among female sex workers in Lima, Peru.

Female sex workers (FSWs) are at high risk of human papillomavirus (HPV) infection. Questionnaires were administered to 200 FSWs aged 18-26 years in Lima, Peru, to gather risk behaviours, and cervical swab samples were collected for Pap smears and HPV DNA testing as part of a longitudinal study. Participants reported a median of 120 clients in the past month, and 99.2% reported using condoms with clients. The prevalence of any HPV in cervical samples was 66.8%; 34 (17.1%) participants had prevalent HPV 16 or 18, and 92 (46.2%) had one or more oncogenic types. Fifteen women had abnormal Pap smears, 13 of which were HPV DNA positive. Fewer years since first sex was associated with oncogenic HPV prevalence in a model adjusted for previous sexually transmitted infection (STI) status and condom use with partners (prevalence ratio = 0.77, 95% confidence interval [CI] = 0.60-0.97). Our data confirm the high rates of HPV transmission among FSWs in Peru, highlighting the need for early and effective strategies to prevent cervical cancer.

Oral sex practices, oral human papillomavirus and correlations between oral and cervical human papillomavirus prevalence among female sex workers in Lima, Peru.

Few data exist on oral human papillomavirus (HPV) prevalence in female sex workers (FSWs). Information regarding oral sex practices of 185 Peruvian FSWs, 18-26 years of age, was obtained via survey and compared with HPV testing results of oral rinse samples. Oral HPV prevalence was 14/185 (7.6%); four (28.9%) HPV genotypes were carcinogenic. One hundred and eighty-two participants reported having had oral sex; 95% reported condom use during oral sex with clients and 9.5% with partners. Women who had oral sex more than three times with their partners in the past month were more likely to have oral HPV than women who had oral sex three times or less (P = 0.06). Ten (71.4%) women with oral HPV were HPV-positive at the cervix; conversely 8.3% of women with cervical HPV were HPV-positive in the oral cavity. The prevalence of oral HPV was relatively low, considering the high rates of oral sex practiced by these women.

A theoretical approach to the photochemical activation of matrix isolated aluminum atoms and their reaction with methane.

The photochemical activation of Al atoms in cryogenic matrices to induce their reaction with methane has been experimentally studied before. Here, a theoretical study of the nonadiabatic transition probabilities for the ground ((2)P:3s(2)3p(1)) and the lowest excited states ((2)S:3s(2)4s(1) and (2)D:3s(2)3d(1)) of an aluminum atom interacting with a methane molecule (CH(4)) was carried out through ab initio Hartree-Fock self-consistent field calculations. This was followed by a multiconfigurational study of the correlation energy obtained by extensive variational and perturbational configuration interaction analyses using the CIPSI program. The (2)D state is readily inserted into a C-H bond, this being a prelude to a sequence of avoided crossings with the initially repulsive (to CH(4)) lower lying states (2)P and (2)S. We then use a direct extension of the Landau-Zener theory to obtain transition probabilities at each avoided crossing, allowing the formation of an HAlCH(3) intermediate that eventually leads to the final pair of products H+AlCH(3) and HAl+CH(3).

Internet as a tool to access high-risk men who have sex with men from a resource-constrained setting: a study from Peru.

OBJECTIVES: In Peru, current interventions in high-risk men who have sex with men (MSM) reach a limited number of this population because they rely solely on peer education. The objective of this study was to assess the use of the internet as an alternative tool to access this population. METHODS: Two nearly identical banner ads-both advertising an online survey but only one offering free HIV/syphilis tests and condoms-were displayed randomly on a Peruvian gay website. RESULTS: The inclusion of the health incentive increased the frequency of completed surveys (5.8% vs 3.4% of delivered impressions; p<0.001), attracting high-risk MSM not previously tested for HIV but interested in a wide variety of preventive Web-based interventions. Eleven per cent (80/713) of participants who said they had completed the survey offering free testing visited our clinic: of those who attended, 6% had already been diagnosed as having HIV, while 5% tested positive for HIV. In addition, 8% tested positive for syphilis. CONCLUSIONS: The internet can be used as a tool to access MSM in Peru. The compensation of a free HIV/syphilis test increased the frequency of participation in our online survey, indicating that such incentives may be an effective means of reaching this population. However, as only a small percentage of participants actually reported for testing, future research should develop and assess tailored internet interventions to increase HIV/STI testing and delivery of other prevention services to Peruvian MSM.

Valores de referencia del antígeno prostático específico / Refence values of prostate specific antigen

En el presente estudio se determinaron los valores de referencia del PAS (antígeno prostático específico) en individuos en estado de salud para patologías prostáticas, teniendo en cuenta la falta de información en individuos en estas condiciones. Se incluyeron en el estudio, 618 individuos del sexo masculino, con edades comprendidas entre 40 y 69 años, que concurrieron al laboratorio “Medical Center” entre 1999 y 2001, procedentes de consultorios urológicos, con solicitudes de estudios laboratoriales. Para la selección de los individuos se siguieron las recomendaciones del Panel de Expertos en Teoría de los Valores de Referencia de la IFCC (Federación Internacional de Química Clínica). Individuos sin patología prostática, clínicamente sin dificultad en la micción y examen dígito rectal normal, con resultados negativos a los auxiliares de diagnóstico citoscopía y ecografía. Se realizó la medición con el método inmunoensayo de partículas (MEIA), IMX Abbott, USA. En primer término se analizó el tipo de distribución de los valores de concentración de PAS de todos los individuos, empleando el test de Kolmogorov ­ Smirnov. Los valores de referencia de PAS obtenidos, entre los percentiles 2,5% y 97,5% mostraron diferencias de valores por grupo etário, con aumento progresivo (Kruskall­Wallis, p<0,0001). Los valores de referencia del PAS en ng/mL, fueron: de 40 a 49 años de 0,25 a 2; de 50 a 59 años de 0,64 a 3,24; de 60 a 69 años de 0,54 a 3,7. Los valores obtenidos servirán de guía para aplicar criterios de medicina preventiva que ayudaran al profesional de la salud en el diagnóstico precoz de patología prostática.

Development of prostate hyperplasia is an almost universal phenomenon in aging men. The PSA levels in serum are useful in the clinical evaluation in men over the age of 45. The objective of this study was to establish the reference values of prostate specific antigen (PSA) in serum in a selected Paraguayan population by microparticle enzimoimmunoassay MEIA. Six hundred eighteen people were evaluated with ages ranging from 40 to 69 years old who attended to “Laboratory Medical Center” in Asunción, Paraguay during 1999­2001. All were subjected to digital rectal examination, biopsy and echograph to assure the prostate disease free state. The International Federation of Chemical Chemistry (IFCC) reference value guidelines were used for individual selection. PSA concentrations were determined by microparticle enzimoimmunoassay (Autoanalyzer IMXABBOT/USA). The PSA concentration was presented as percentiles since neither the values nor the logarithms fitted into a normal distribution (Kolmogorov­Smirnov Test). Therefore, a nonparametric test (Kruskal­Wallis) was used for the estimation of differences between datum groups. According to age, our data showed statistical differences (p<0,0001). At increasing levels of PSA: 40 ­ 49 years old the serum value ranged from 0.25 ­ 2.0 ng/mL, 50 ­ 59 years old from 0.64 to 3.24 ng/mL and 60 ­ 69 from 0.54 to 3.7 ng/mL. These data represented the percentiles 2.5% and 97.5%. These PSA reference values will serve in screening programs as tools to detect prostate diseases in our population.

Origin of Mayans according to HLA genes and the uniqueness of Amerindians.

The HLA allele frequency distribution of the Mayans from Guatemala was studied and compared with those of other First American Natives and worldwide populations (a total of 12,364 chromosomes and 6182 individuals from 60 different populations). The main conclusions were (1): the closest Amerindian group to Mayans is the Arhuacs, who were the first recorded Caribbean Islands' inhabitants (2). Mayans are not so close to Mesoamerican Zapotec, Mixe and Mixtec Amerindians, who genetically cluster together. Mixe had been related to Mayans only on linguistic bases (3). DRB1*0407 and DRB1*0802 alleles are found in 50% of Mayans; these alleles are also found in other Amerindians, but the Mayans' high frequencies may be showing a founder effect for this Mesoamerican-Caribbean population (4). Extended Mayan specific HLA haplotypes are described for the first time (5). Language and genes do not completely correlate in microgeographical studies (6). Significant genetic input from outside is not noticed in Meso and South American Amerindians according to the genetic analyses; while all world populations (including Africans, Europeans, Asians, Australians, Polynesians, North American Na-Dene Indians and Eskimos) are genetically related. Meso and South American Amerindians tend to remain isolated in the neighbour joining analyses.