Maria Evangelina Ferreira Fonseca

Placental pathology in congenital rubella

Summary Two groups of placentae from 18 cases of maternal rubella were examined morphologically and virologically. Placentae in Group I (four cases) had a mean gestational age of 21±1.9 weeks, whilst those in Group 2 (14 cases) had a mean gestational age of 38±2.8 weeks. A tendency to hypoplasia was observed. The microscopic lesions were similar to those found in other viral infections but in each group some specific features were noted. Only placentae of Group 1 showed nodules of villi agglutinated by fibrin. This lesion suggested recent maternal infection. Attention is drawn to the presence of abnormal areas of lobular rarefaction due to dysmaturity of villous stem and terminal villi. This aspect was more diffuse and accentuated in Group 2 placentae. Villitis of reactive, necrotic, proliferative and reparative types was seen only in placentae of Group 2. Devastating villitis was not observed. Inclusions in placental cells suggested rubella infection. The lesions were non-specific and hence stress the need for virological examination of the placenta, immunofluorescence studies and electron microscopy to confirm the diagnosis.

FETO-PLACENTARY PATHOLOGY IN HUMAN PARVOVIRUS B19 INFECTION

In view of the scarce references concerning the histological data in congenital parvovirus human B19 infection, we intend to provide a description of the pathological features observed in six autopsies. The virus was detected by DNA hybridization (ISH-DBH), PCR and electronmicroscopy (EM) in paraffin-embedded feto-placentary tissues. These cases constitute a subset from 86 Non Immunologic Hydrops Fetalis (NIHF) cases, in which a systemic complex of inflammatory/degenerative lesions of unknown etiology was visualized by optical microscopy. In one case a syphilitic process was detected, typefying a double infection. All fetuses showed a similar pathology--hydrops, hepato-splenomegaly, lung hypoplasia and erythroblastemia, the specific histological feature being the presence of intranuclear inclusions in the erythroid progenitors, in the erythropoietic visceral tissue and in blood marrow. Complex cardiopathy allied to abnormal lung lobulation and polisplenia were observed once; in 2 cases endocardial fibroelastosis was diagnosed. The pulmonary lesions were represented by dysmaturity allied to interstitial mononuclear infiltration. The hepatic consisted of cholestasis, portal fibrosis, canalicular proliferation, hemossiderosis, focal necroses and giant cell transformation. The central nervous system lesions were predominantly anoxic although the autolysis impaired a correct diagnosis.

Human parvovirus B19 infection and hydrops fetalis in Rio de Janeiro, Brazil

Formalin-fixed paraffin embedded lung and liver tissue from 23 cases of non immune hydrops fetalis and five control cases, in which hydrops were due to syphilis (3) and genetic causes (2), were examined for the presence of human parvovirus B19 by DNA hybridisation. Using in situ hybridisation with a biotynilated probe one positive case was detected. Using 32P-labelled probes in a dot blot assay format, five further positives were obtained. These were all confirmed as positive by a nested polymerase chain reaction assay. Electron microscopy revealed virus in all these five positive cases. The six B19 DNA positive cases of hydrops fetalis were from 1974, 1980, 1982, 1987 and 1988, four of which occurred during the second half of the year, confirming the seasonality of the disease.

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.

Surface vesicles : A possible function in commensal relations of Bacteroides fragilis

Surface vesicles (SV) defined by electron microscopy as outer membrane (OM) extrusions were detected in Bacteroides fragilis strains from distinct sources. A partial identity between SV and OM electrophoretic protein profiles, in addition to the microscopic analysis, may suggest the designation of OMSV. Sialidase activity, a virulence determinant, was associated with these sub-cellular structures in all the strains, but in an inverse relation to the vesicle quantity per cell. A commensal strain, previously defined as avirulent in an animal model, presented the lowest vesicle-associated sialidase activity and the greatest SV expression as opposed to what happened with clinical and environmental strains. These results seem to suggest that these surface components have a function in commensal stages of B. fragilis.

Molluscum contagiosum: serology and electron microscopy findings in twenty one patients

Twenty one cases of molluscum contagiosum virus disease were collected for electron microscopical and serological tests. Molluscum virus was detected in the crust, inside the vacuoles formed in the keratinocytes cells. The patients developed specific antibodies to the virus detected by complement fixation test.

Ecology of a plant growth-promoting strain of Pseudomonas fluorescens colonizing the maize endorhizosphere in tropical soil

Pseudomonas fluorescens strain BR-5 stimulated the growth of maize in a natural soil and inhibited fungal root pathogens in vitro. Strain BR-5 was detected inside plant cells, indicating that it is able to colonize the endorhizosphere. No significant effect was detected on soil or ectorhizosphere microbial population after inoculation of strain BR-5 onto seeds.

Morphological and virological studies in six autopsies of children with adenovirus pneumonia

Pulmonary lesions compatible with adenovirus infection were detected by gross and microscopic examination of autopsy tissues from children aged from 5 to 34 months. Hepatic lesions indicative of systemic infection were also found in four of the children. The viral etiology was confirmed in three cases by in-situ hybridization, electron-microscopy and immunofluorescence performed in paraffin-embedded tissues, and in one case by cell culture isolation of adenovirus type 2 from nasopharyngeal exudate. Routine testing by methods additional to conventional light microscopy would probably have revealed a larger number of adenovirus infections among the 1,103 autopsy records analyzed in this study.

An attempt to cultivate human rotavirus in human leukocytes culture (preliminary report)

Experimentos preliminares da permissividade de cultura de leucocitos humanos estimulados com mitogeno frente a infeccao pelo rotavirus humano foram realizados por microscopia eletronica. Observamos que, celulas mo-nonucleadas, mantidas em cultura, apos estimulacao com fitohemaglutinina (PHA) colhidas 36 horas pos-infeccao apresentavam muitas particulas virais no citoplasma. Verificamos, tambem, muitas particulas virais associadas a fragmentos celulares, varias celulas em degeneracao e alguns linfocitos pequenos intactos. Nao presenciamos particulas virais em celulas colhidas previamente (12 e 24 horas p.i.) e nas culturas controle (sem tratamento com PHA). Sugerimos que o rotavirus humano pode se replicar em culturas de leucocitos humanos estimulados com PHA.

Human papillomavirus detection in genital lesions by in situ hybridization and ultrastructural observations

Detection of papillomavirus DNA in situ hybridization technique was performed in 29 symptomatic patients (6 males and 23 females) during the period of 1989-1991 at the Clinic for Sexually Transmitted Diseases, Universidade Federal Fluminense, State of Rio de Janeiro. All the male patients had condyloma acuminata. Only HPV 6/11 were found in these lesions. Clinical features in the female patients included vulvar condyloma acuminata, bowenoid papulosis, flat cervical condyloma, cervical condyloma acuminatum and cervical intraepithelial neoplasia grade II (CIN II). We also found cases of condyloma acuminata associated to vulvar intraepithelial neoplasia grade III (VIN III), as well as to vaginal invasive carcinoma. HPV 6/11 and 16/18 were found in vulvar condyloma acuminata. Mixed infection by 6/11-16/18 HPV were also seen in these lesions as well as in the patient who had cervical condyloma acuminatum. HPV 16/18 were found in the condyloma acuminatum plus VIN III and in the CIN II lesions. We have found HPV 31/33/51 in the specimen of condyloma acuminatum plus invasive carcinoma. In order to investigate the ultrastructural aspects of HPV infection in genital tissue, the biopsies of three female patients were observed under electron microscope. Mature virus particles were found in the cells of a condyloma acuminatum as well as in the condyloma acuminatum plus invasive carcinoma case. In another sample, chromosome breakages were found in the nuclei of the infected cells although no viral particles were observed.