Implantação intracerebral experimental de sarcomas

Estudo histopatológico da implantação intracerebral de sarcomas, realizado em ratos (fibrosarcoma) e em camundongos (sarcoma 180). A implantação intracerebral de fibrosarcoma desenvolveu, em cerca de 45 dias, neoplasia relativamente bem delimitada, com pequena infiltração do parênquima nervoso adjacente, nunca se propagando a maiores distãncias devido a forte coesão entre as suas células, com grande diferenciação de fibrilas reticulares e de colágeno. Ao contrário, a inoculação do sarcoma 180, principalmente sob a forma ascítica, levou rapidamente a um quadro de forte hipertensão intracraniana, com disseminação das células neoplásticas pelos espaços subaracnoideanos e intraventriculares. Ambas as neoplasias propagavam-se pelos espaços subaracnoideanos e intraventriculares. Ambas as neoplasias propagavam-se pelos espaços perivasculares, porém o faziam de maneira diversa; o sarcoma 180 tinha uma disseminação muito intensa e rápida, que se fazia a longas distâncias, enquanto que o fibrossarcoma somente se disseminava nos vasos próximos à neoplasia em desenvolvimento. Tomando por base observações próprias e outras colhidas na bibliografia especializada, conclui-se que os agentes etiológicos destes tumores exercem sua ação sobre tipos celulares diferentes.

Germinomas cerebrais (teratomas atípicos da pineal)

São estudados três casos de germinomas cerebrais, sendo um tópico, da região pineal, e dois ectópicos, chamados germinomas supra-selares ou quiasmáticos. Estes últimos parecem ser mais agressivos que os seus congeneres tópicos, pois alem de se disseminarem pelas cisternas basais, costumam infiltrar as paredes do III ventrículo, fórnix, hipotálamo, nervos e quiasma ópticos. Caracteristicamente produzem um enorme aumento das proteínas liquóricas, desacompanhado de uma pleocitose proporcional. As proteínas liquóricas aumentadas sao globulinas cujas reações mostram-se fortemente positivas, possivelmente produzidas pelas celulas de aspecto linfocitario que constituem parte desta neoplasia. O aumento das proteinas liquoricas e tao acentuado que em presenca de uma crianca ou adolescente com sindrome de hipertensão intracraniana, hiperproteinoraquia sem pleocitose e sinais clínicos ou radiológicos sugestivos de localização na base do crânio a possibilidade de um germinoma quiasmático deve ser seriamente considerada, pois o quadro e muito sugestivo.

Produção e padronização dos antígenos de Paracoccidioides brasiliensis (Pb), Histoplasma capsulatum (Hc) e Aspergillus fumigatus (Af) para uso no imunodiagnóstico: comparação entre as técnicas de imunodifusão e imunoeletroosmoforese

Foram produzidos antígenos solúveis de P. brasiliensis, H. capsulatum e A. fumigatus e padronizados nas técnicas de imunodifusão dupla (IDD) e imunoeletroosmoforese (IEOF). A especificidade dos antígenos foi testada utilizando-se 96 soros de pacientes com paracoccidioidomicose, histoplasmose, aspergilose, candidíase sistêmica, esporotricose, tuberculose, neoplasia pulmonar, leishmaniose tegumentar e visceral e em 18 indivíduos sadios. Na IDD, a especificidade foi de 100% usando-se como critério de positividade linhas de precipitação com identidade total com soro de referência. Entretanto na IEOF, a especificidade variou de acordo com o antígeno testado, sendo observadas reações cruzadas com antígeno de P. brasiliensis frente a soros de pacientes com histoplasmose (16,7%) e leishmaniose tegumentar (10%) e com antígeno de H. capsulatum frente a soros de pacientes com paracoccidioidomicose (31,8%) e leishmaniose tegumentar (10%). Ambas as técnicas mostraram a mesma sensibilidade para o sorodiagnóstico de paracoccidioidomicose, histoplasmose e aspergilose, respectivamente 100%, 83,3% e 100%. A grande sensibilidade e especificidade da IDD observadas nos soros desses pacientes, aliadas à fácil reprodutibilidade e baixo custo, fazem esta técnica muito apropriada como procedimento de rotina, para a triagem de pacientes sintomáticos respiratórios.

Evaluation of the rabbit as a model for chagas' disease: I. Parasitological studies

In order to investigate the value of the rabbit as an experimental model for Chagas' disease, 72 animals have been inoculated by intraperitoneal and conjunctival route with bloodstream forms, vector-derived metacyclic trypomastigotes and tissue culture trypomastigotes of Trypanosoma cruzi strains Y, CL and Ernane. In 95.6% of the animals trypomastigotes had been detected at the early stages of infection by fresh blood examination. The course of parasitemia at the acute phase was strongly influenced by the parasite strain and route of inoculation. At the chronic phase parasites had been recovered by xenodiagnosis and/or hemoculture in 40% of the examined animals. The xenodiagnosis studies have shown selective interactions between the T. cruzi strains and the four species of vectors used, inducing significant variability in the results. The data herein present are consistent with the parasitological requirements established for a suitable model for chronic Chagas' disease.

Experimental Chagas' disease in dogs

This paper describes the development of experimental Chagas' disease in 64 out-bred young dogs. Twenty-nine animals were inoculated with the Be-62 and 35 with Be-78 Trypanosoma cruzi strains. Twenty-six were infected with blood trypomastigotes by different inoculation routes and 38 with metacyclic trypomastigotes from the vector via the conjunctival route. Twenty of the 26 dogs infected with blood trypomastigotes were autopsied during the acute phase. Eleven died spontaneously and nine were sacrificed. Six remained alive until they died suddenly (two) or were autopsied (four). Twelve of the 38 dogs infected with metacyclic trypomastigotes evolved naturally to the chronic phase and remained alive for 24-48 months. The parasitemia, clinical aspects and serology (IgM and IgG) as well as electrocardiogram, hemogram and heart anatomo-histopathologic patterns of acute and chronic cardiac forms of Chagas' disease as seen in human infections, were reproduced. The most important finding is the reproductibility of diffuse fibrosing chronic chagasic cardiopathy in all dogs infected with Be-78 T. cruzi strain autopsied between the 90th and 864th days of infection. Thus, the dog can be considered as a suitable experimental model to study Chagas' disease according to the requisites of the World Health Organization (1984). Futhermore the animal is easily obtained and easy to handle and maintain in experimental laboratory conditions.

Prevalence of human papillomavirus DNA in female cervical lesions from Rio de Janeiro, Brazil

A hundred-sixty paraffin-embedded specimens from female cervical lesions were examined for human papillomavirus (HPV) types 6, 11, 16 and 18 infections by non-isotopic in situ hybridization. The data were compared with histologic diagnosis. Eighty-eight (55) biopsies contained HPV DNA sequences. In low grade cervical intraepithelial neoplasias (CIN I), HPV infection was detected in 78.7 of the cases, the benign HPV 6 was the most prevalent type. HPV DNA was detected in 58 of CIN II and CIN III cases and in 41.8 of squamous cell carcinomas (SCC). Histologically normal women presented 20 of HPV infection. Oncogenic HPV was found in 10 of these cases, what may indicate a higher risk of developing CINs and cancer. Twenty-five percent of the infected tissues contained mixed infections. HPV 16 was the most common type infecting the cervix and its prevalence raised significantly with the severity of the lesions, pointing its role in cancer pathogenesis. White women presented twice the cervical lesions of mulatto and African origin women, although HPV infection rates were nearly the same for the three groups (approximately 50). Our results showed that HPV typing by in situ hybridization is a useful tool for distinguishing between low and high risk cervical lesions. Further studies are required to elucidate risk factors associated with HPV infection and progression to malignancy in Brazilian population.

Human papillomavirus infection and cervical cancer in Brazil: a retrospective study

Two hundred and thirty paraffin-embedded biopsies obtained from female cervical lesions were tested for the presence of human papillomavirus (HPV) types 6/11,16/18 and 31/33/35 DNA using non-isotopic in situ hybridization. Specimens were classified according to the Bethesda System in low grade squamous intraepithelial lesion (LSIL), high grade SIL (HSIL) and squamous cell carcinoma (SCC). HPV prevalence ranged from 92.5% in LSIL to 68.5% in SCC. Benign types were prevalent in LSILs while oncogenic types infected predominantly HSILs and SCC. HPV infection showed to be age-dependent, but no significant relation to race has been detected. Patients were analyzed through a five-year period: 20.7% of the lesions spontaneously regressed while 48.9% persisted and 30.4% progressed to carcinoma. Patients submitted to treatment showed a 19.4% recurrence rate. High risk types were present in 78.6% (CrudeOR 13.8, P=0.0003) of the progressive lesions, and in 73.7% of the recurrent SILs (COR 19.3, P=0.0000001). Possible co-factors have also been evaluated: history of other sexually transmitted diseases showed to be positively related either to progression (Adjusted OR 13.0, P=0.0002) or to recurrence (AOR 17.2, P=0.0002) while oral contraceptive use and tobacco smoking were not significantly related to them (P>0.1). Association of two or more co-factors also proved to be related to both progression and recurrence, indicating that they may interact with HPV infection in order to increase the risk of developing malignant lesions.

Prevalence of human papillomavirus type 16 variants in the Federal District, Central Brazil

We report the prevalence of human papillomavirus type 16 (HPV-16) variants in women with cervical lesions from the Federal District, Central Brazil. We analyzed 34 HPV-16 samples, identifying the sequence variations of E6 and L1 genes and correlating variant frequency with disease status. The most prevalent HPV-16 variant was the European (50%), followed by Asian-American (41.2%), African-1 (5.9%), and African-2 (2.9%). European and non-European variants appeared in equal frequencies among the cytological types of lesions - atypical squamous or glandular cells of undetermined significance, cytological alterations suggesting HPV infection, cervical intraepithelial neoplasias, squamous cell carcinoma, and adenocarcinoma.

First record of human trichinosis in Chile associated with consumption of wild boar (Sus scrofa)

The first South American case of human trichinosis, resulting from the consumption of roast wild boar (Sus scrofa) is reported in Chile. The patient presented fever, diarrhea, myalgias, facial edema, sub-conjunctival reddening, photophobia, eosinophilia, and elevated glutamic oxalacetic transaminase. The diagnosis was confirmed by two immunoenzymatic tests (ELISA) using somatic and excretion-secretion antigens.

Frequency and types of human papillomavirus among pregnant and non-pregnant women with human immunodeficiency virus infection in Recife determined by genotyping

Women with human immunodeficiency virus (HIV) infection present a higher risk of infection by the human papillomavirus (HPV) and cervical cancer. To determine HPV genotypes and frequencies among HIV-positive women, an analytical cross-sectional study was carried out on 147 women (51 were pregnant and HIV-positive, 45 pregnant and HIV-negative and 51 HIV-positive and not pregnant), who were attended at a maternity hospital in Recife between April 2006-May 2007. They answered a questionnaire and underwent a gynaecological examination, with samples collected for HPV investigation by PCR, hybrid capture II, oncotic colpocytology (Papanicolau) and colposcopy. The frequency of HPV DNA was 85.3% (122/143), with a high proportion of HPV types that have been identified as high risk for cervical cancer. Among HIV-positive pregnant women, there was an HPV prevalence of 96% (48/50), of whom 60.4% (29/48) were high-risk. HPV 16, 58, 18, 66 and 31 were the most frequent types. Colpocytological abnormalities were observed in 35.3% (18/51) of HIV-positive non-pregnant women, 21.6% (11/51) of HIV-positive pregnant women and 13.3% (6/45) of HIV-negative pregnant women with a predominance of low-level lesions. A high prevalence of HPV infection was identified, especially with the high-risk types 16, 58, 18 and 66. This study identified high-risk HPV types in all three groups examined (HIV-positive pregnant women, HIV-negative pregnant women and HIV-positive not pregnant), characterising its distribution in this setting.

Prevalence of human papillomavirus and Epstein-Barr virus DNA in penile cancer cases from Brazil

Penile cancer is a potentially mutilating disease. Although its occurrence is relatively rare worldwide, penile cancer rates can be high in developing countries. A few studies have been conducted on the involvement of human papillomavirus (HPV) in penile carcinoma, which have found HPV present in 30-70% of penile malignant lesions, with a higher prevalence of HPV 16 and 18. It has been assumed that cofactors, such as Epstein-Barr virus (EBV) infections, may play a role in the progression of penile neoplasia. The aim of this study was to determine HPV and EBV prevalence in 135 penile malignant lesions from Brazilian men through the use of MY09/11 polymerase chain reaction (PCR), type-specific PCR and restriction fragment length polymorphism analysis. HPV prevalence among the men tested was 60.7%. Of the men who tested positive, 27 presented with HPV 16 (29.7%), five with HPV 18 (5.5%), 21 with HPV 45 (23.1%) and nine with HPV 6 (9.9%). Seven mixed infections were detected (9.2%), while 11 cases remained untyped (13.4%). Regarding EBV positivity, 46.7% of the samples contained EBV DNA with EBV-1 as the most prevalent type (74.6%). More than 23% of the men were co-infected with both HPV and EBV, while 35% presented exclusively with HPV DNA and 20% presented only with EBV DNA. Penile carcinoma aetiology has not been fully elucidated and the role of HPV and EBV infections individually or synergistically is still controversial. Hence, more studies are needed to determine their possible role in carcinogenesis.

Comparison of the infectivity of Trypanosoma cruzi insect-derived metacyclic trypomastigotes after mucosal and cutaneous contaminative challenges

Trypanosoma cruzi infects humans when infected triatomine vector excreta contaminate breaks in skin or mucosal surfaces. T. cruzi insect-derived metacyclic trypomastigotes (IMT) invade through gastric mucosa after oral challenges without any visible inflammatory changes, while cutaneous and conjunctival infections result in obvious local physical signs. In this study we compared the infectivity of T. cruzi IMT in mice after cutaneous and oral contaminative challenges simulating natural infections. The 50% infective dose (ID50) for oral challenge was 100 fold lower than the ID50for cutaneous challenge, indicating that oral mucosal transmission is more efficient than cutaneous transmission.

Acute dacryocystitis: another clinical manifestation of sporotrichosis

Sporotrichosis associated with exposure to domestic cats is hyperendemic in Rio de Janeiro, Brazil. A review of the clinical records at our institute revealed four patients with clinical signs of dacryocystitis and a positive conjunctival culture for Sporothrix who were diagnosed with Sporothrix dacryocystitis. Three patients were children (< 13 years of age) and one patient was an adult. Two patients reported contact with a cat that had sporotrichosis. Dacryocystitis was associated with nodular, ulcerated lesions on the face of one patient and with granulomatous conjunctivitis in two patients; however, this condition manifested as an isolated disease in another patient. All of the patients were cured of the fungal infections, but three patients had chronic dacryocystitis and one patient developed a cutaneous fistula. Sporotrichosis is usually a benign disease, but may cause severe complications when the eye and the adnexa are affected. Physicians, especially ophthalmologists in endemic areas, should be aware of the ophthalmological manifestations and complications of sporotrichosis.

Prevalence of human papillomavirus infection, distribution of viral types and risk factors in cervical samples from human immunodeficiency virus-positive women attending three human immunodeficiency virus-acquired immune deficiency syndrome reference centres in northeastern Brazil

Human immunodeficiency virus (HIV)-positive patients have a greater prevalence of coinfection with human papillomavirus (HPV) is of high oncogenic risk. Indeed, the presence of the virus favours intraepithelial squamous cell lesion progression and may induce cancer. The aim of this study was to evaluate the prevalence of HPV infection, distribution of HPV types and risk factors among HIV-positive patients. Cervical samples from 450 HIV-positive patients were analysed with regard to oncotic cytology, colposcopy and HPV presence and type by means of polymerase chain reaction and sequencing. The results were analysed by comparing demographic data and data relating to HPV and HIV infection. The prevalence of HPV was 47.5%. Among the HPV-positive samples, 59% included viral types of high oncogenic risk. Multivariate analysis showed an association between HPV infection and the presence of cytological alterations (p = 0.003), age greater than or equal to 35 years (p = 0.002), number of partners greater than three (p = 0.002), CD4+ lymphocyte count < 200/mm3 (p = 0.041) and alcohol abuse (p = 0.004). Although high-risk HPV was present in the majority of the lesions studied, the low frequency of HPV 16 (3.3%), low occurrence of cervical lesions and preserved immunological state in most of the HIV-positive patients were factors that may explain the low occurrence of precancerous cervical lesions in this population.

Bonafide, type-specific human papillomavirus persistence among HIV-positive pregnant women: predictive value for cytological abnormalities, a longitudinal cohort study

This study investigated the rate of human papillomavirus (HPV) persistence, associated risk factors, and predictors of cytological alteration outcomes in a cohort of human immunodeficiency virus-infected pregnant women over an 18-month period. HPV was typed through L1 gene sequencing in cervical smears collected during gestation and at 12 months after delivery. Outcomes were defined as nonpersistence (clearance of the HPV in the 2nd sample), re-infection (detection of different types of HPV in the 2 samples), and type-specific HPV persistence (the same HPV type found in both samples). An unfavourable cytological outcome was considered when the second exam showed progression to squamous intraepithelial lesion or high squamous intraepithelial lesion. Ninety patients were studied. HPV DNA persistence occurred in 50% of the cases composed of type-specific persistence (30%) or re-infection (20%). A low CD4+T-cell count at entry was a risk factor for type-specific, re-infection, or HPV DNA persistence. The odds ratio (OR) was almost three times higher in the type-specific group when compared with the re-infection group (OR = 2.8; 95% confidence interval: 0.43-22.79). Our findings show that bonafide (type-specific) HPV persistence is a stronger predictor for the development of cytological abnormalities, highlighting the need for HPV typing as opposed to HPV DNA testing in the clinical setting.