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Biomedical subjects

E Medeiros

Publications and source records attributed to E Medeiros.

15 recordsLinked to original sources

Pontomedullary sulcus infarct: a variant of lateral medullary syndrome.

With the advent of magnetic resonance imaging (MRI) technology, it is now possible to identify and determine the precise location of medullary infarcts. The lateral part of the medulla is most commonly affected by infarction. Classifications of lateral medullary infarcts are usually based on anatomical data, using rostrocaudal and dorsoventral axes to establish correlations with clinical symptoms. Different subtypes of lateral medullary syndrome, depending on location, shape and size of the infarct, have been described in the literature. We report a rare case of a patient presenting with an unusual clinical picture in relation to an infarct specifically located in the lateral part of the pontomedullary sulcus.

Cerebral Infarction↗

Enterococcus faecalis resistant to vancomycin and teicoplanin (VanA phenotype) isolated from a bone marrow transplanted patient in Brazil.

We report for the first time in Brazil, a patient from whom an Enterococcus faecalis VanA phenotype was isolated. Glycopeptide resistance is not commonly observed in Enterococcus faecalis, so this finding is of great concern since this species is responsible for 90% of enterococcal infections in Brazil. The isolate was recovered from a surveillance rectal swab culture from a patient with acute lymphocytic leukemia (ALL). Identification to the species level was performed by conventional biochemical tests and Vitek GPI cards. Antimicrobial susceptibility testing was evaluated by use of broth microdilution and Etest (AB BIODISK, Solna, Sweden) methods. The isolate was identified as E. faecalis and was considered resistant to both vancomycin (MIC, > 256 microg/mL) and teicoplanin (MIC, 256 microg/mL). The isolate also showed high level resistance to gentamicin and streptomycin (MICs, > 1024 microg/mL), but was considered susceptible to ampicillin (MIC, 4 microg/mL). Although the frequency of enterococcal infections is very low in most Latin America countries, the finding of glycopeptide (VanA) resistance in E. faecalis increases concern about apreading antimicrobial resistance in this region.

Adult↗

Trypanosoma cruzi meningoencephalitis in HIV-infected patients.

Five cases of Trypanosoma cruzi meningoencephalitis in HIV-infected patients are reported. All patients presented with mass lesions on head computed tomographic scan, trypanosomes in the cerebrospinal fluid and failure to respond to antitoxoplasmosis therapy. Benznidazole therapy was associated with clinical improvement in 1 patient. Another 4 patients had T cruzi identified in a peripheral smear. T cruzi needs to be considered in the differential diagnosis of HIV-infected patients with central nervous system mass lesions if they have a history of appropriate exposure.

AIDS-Related Opportunistic Infections↗

Cytomegalovirus infection in sex partners: evidence for sexual transmission.

To examine the hypothesis that cytomegalovirus (CMV) is sexually transmitted, we determined the prevalences of antibody to CMV and viral shedding in 63 male sex partners of women with or without CMV infection, and CMV isolates from infected couples were compared by DNA restriction enzyme analysis. The prevalence of seropositivity by enzyme-linked immunosorbent assay was 31 (74%) of 42 men whose female partners were seropositive compared with five (31%) of 16 men whose partners were seronegative (P = .008). CMV was isolated from the semen or urine of four (22%) of 18 men whose female partners shed CMV from the cervix or urine compared with none of 42 whose partners were culture negative (P = .013). DNA restriction enzyme typing of CMV isolates from three pairs of sex partners showed that two of the couples were infected with common strains; epidemiologically unrelated isolates gave distinct patterns. Heterosexual contact is a major mode of transmission of CMV among some young adults.

Adult↗

An avian oncovirus mutant (SE 21Q1b) deficient in genomic RNA: biological and biochemical characterization.

We have isolated a nonconditional mutant of PR-RSV-E with unique properties. This virus (SE 21Q1b) is shed from a continuously growing culture of transformed quail cells. 21Q1b virions are unable to transform or replicate in other quail or chicken cells after exogenous infection, despite the fact that the viral particles contain normal envelope glycoproteins, internal structural proteins and RNA-dependent DNA polymerase. The lack of infectivity of 21Q1b virions is a consequence of the failure to package genomic 39S RNA. Instead, these virions contain a mixture of heterogenous-sized polyadenylated cellular RNAs and 4S RNA. Less than 1% of the encapsulated RNA is viral-specific, although in the 21Q1b-producing cells, amounts of 39S, 28S and 21S viral RNAs comparable to those in wild-type virus-infected cells are synthesized and function as mRNAs for the viral proteins. Thus 21Q1b can be considered an RNA packaging mutant. Superinfection of 21Q1b cells with either RAV-1 or PR-A leads to production of about 10% or more of the normal titer of superinfecting virus, but none of the 21Q1b genetic markers are rescued. After superinfection, the 21Q1b cells continue to synthesize 21Q1b particles containing cellular RNAs in the same amounts as before infection. Thus superinfection does not appear to "switch off" the aberrant packaging of cellular RNA, but allows packaging of the superinfecting RNA. One explanation for the phenotype of 21Q1b is that the genome is lacking a signal necessary for efficient genomic RNA packaging (but not for translation) and that the 21Q1b genome encodes a "packaging factor" with an altered specificity so that cellular RNAs are efficiently packaged. 21Q1b virions do contain RNA-dependent DNA polymerase which has normal endogenous synthetic activity. The cDNA product made in vitro from detergent-lysed 21Q1b virions hybridizes equally well to uninfected quail and 21Q1b-producing quail cell RNAs, with kinetics suggesting that the endogenous product consists of transcripts of cellular RNAs present in low amounts in the cells.

Avian Sarcoma Viruses↗

Detection and characterization of RNA tumor virus-specific DNA in cells.

RNA tumor virus-specific DNA in cells can be detected by its capacity to 1) alter the reassociation kinetics of labeled double-stranded product of viral RNA-directed DNA polymerase; 2) anneal single-stranded DNA (cDNA) synthesized by viral polymerase; or 3) hybridize labeled viral 70S (genomic) RNA. Duplexes formed with these procedures can be analyzed for fidelity of base pairing, and the integration of viral DNA into the host genome can be established with a simple but stringent technique. We illustrate this methodology as applied to detection of Rous sarcoma virus (RSV)-specific DNA in XC cells and of mouse mammary tumor virus (MMTV)-specific DNA in murine and human tissues.

Animals↗