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At least 793 records · Page 44Linked to original sources
PubMed2006

B-cell posttransplant lymphoproliferative disorders in heart and/or lungs recipients: clinical and molecular-histogenetic study of 17 cases from a single institution.

BACKGROUND: Posttransplantation lymphoproliferative disorders (PTLDs) are heterogeneous lymphoid proliferations representing a major complication of solid organ transplant. This study details the clinicopathological and molecular features of 17 B-cell PTLDs observed in a single center series of 988 heart and/or lung transplant recipients. METHODS: Cases were classified according to World Health Organization lymphoma classification and tested for Epstein-Barr Virus (EBV), clonality, histogenetic phenotypic (CD10, Bcl-6, MUM1, CD138), and genotypic (immunoglobulin and BCL-6 genes somatic hypermutation) markers. RESULTS: This series of 17 PTLDs included: two B-cell monoclonal polymorphic PTLDs and 15 B-cell monomorphic PTLDs (13 diffuse large B-cell lymphomas [DLBCL] and 2 Burkitt lymphomas [BL]). EBV was detected in 9/17 cases. A monoclonal immunoglobulin variable (IGV) genes rearrangement was documented in 17/17 cases; IGV somatic hypermutation was found in 88% of cases, indicating a prevalent origin from germinal center (GC)-experienced B cells. Using immunophenotypic markers, three histogenetic profiles were identified: a) CD10/bcl-6/MUM1/CD138, mimicking GC B-cells; b) CD10-/bcl-6+/MUM1+/CD138-, reminiscent of B-cells at the latest phases of GC reaction; and c) CD10-/bcl-6-/MUM1+/CD138+/-, consistent with preterminally differentiated B-cells. CONCLUSIONS: Correlation between morphology, histogenesis, and EBV status demonstrated a high degree of homogeneity in the two GC-related groups, mostly including EBV-negative cases with BL and DLBCL-centroblastic features; the third group, consisting of post GC EBV-positive cases, was histologically less homogeneous, as it included polymorphic PTLDs and DLBCL with immunoblastic and anaplastic features. The EBV-negative cases with GC histogenetic phenotype showed a slightly better outcome; however, such less aggressive prognostic trend was not confirmed by statistical analysis.

Adolescent↗
PubMed1965

Fine structure of Haemobartonella muris as compared with Eperythrozoon coccoides and Mycoplasma pulmonis.

Tanaka, H. (The Rockefeller University, New York, N.Y.), W. T. Hall, J. B. Sheffield, and D. H. Moore. Fine structure of Haemobartonella muris as compared with Eperythrozoon coccoides and Mycoplasma pulmonis. J. Bacteriol. 90:1735-1749. 1965.-Thin sections of filterable hemolytic anemia agent of rat, now identified as Haemobartonella muris, revealed (i) that the agent is spherical or ellipsoidal and 350 to 700 mmu in size, (ii) that it has a single limiting membrane enclosing granules and some filaments (neither cell wall nor nucleoid was found), and (iii) that it is found preferentially at the surface and sometimes within the cytoplasmic vacuoles of erythrocytes in the circulating blood and bone marrow, and multiplies there through binary fission. No specific structure suggestive of motility was found. From the morphological point of view, Eperythrozoon coccoides was found to be very similar to H. muris, whereas Mycoplasma pulmonis, also covered with a single limiting membrane, differs in its pleomorphism and multiplication. These and some other microorganisms taxonomically between bacteria and viruses were compared morphologically, and their possible classification is discussed.

Animals↗
PubMed1990

The natural history of human immunodeficiency virus infection: a five year study in a London cohort of homosexual men.

Progression rates from asymptomatic to symptomatic Human Immunodeficiency Virus (HIV) infection according to the CDC classification were prospectively studied in a cohort of 172 seropositive homosexual and bisexual men. The median follow-up time was 4 years. The progression from data of entry to the study to any group IV disease was 56% (SE 7%) at 5 years. However, the progression from an estimated date of seroconversion to any group IV disease was 36% (SE 4%) at 5 years. This was more than double the progression rate to AIDS-14% (SE 3%) at 5 years calculated in the same way. There were no differences in progression to AIDS from group IV A (systemic symptoms such as unexplained fever, weight loss or persistent diarrhoea) and group IV C-2 (oral candida or oral hairy leukoplakia). Progression rates to AIDS were significantly lower (p = 0.02) in patients who were under 25 years of age at entry than in those over 25. A review of progression rates to AIDS among homosexual cohorts shows that they tend to be higher than in cohorts of haemophiliac patients, in the early stage of infection. However, when Pneumocystis carinii pneumonia is the outcome measure, progression rates in all studies are remarkably similar.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

A major difference in the strategy of the calici- and picornaviruses and its significance in classification.

Pig kidney (1BRS-2) cells infected with vesicular exanthema virus (VEV), a calicivirus, did not contain any large precursor polypeptides similar to those found when they were infected with foot-and-mouth disease virus (FMDV). The largest induced protein found in the VEV-infected cells had a molecular weight identical with that of the virus structural polypeptide. This difference in strategy between VEV and FMDV, taken in conjunction with the morphological and structural differences described previously, provides strong evidence that the caliciviruses should not be included in the family Picornaviridae.

Animals↗
PubMed1990

Relative prevalence of typical and atypical strains among rotaviruses from diarrheic pigs in conventional swine herds.

Polyacrylamide gel electrophoresis was conducted on genomic RNA extracted from rotaviruses detected in diarrheic pigs from conventional swine herds. Ninety samples contained sufficient virus for RNA band visualization and genome classification. Genome profiles were characteristic of typical group A rotaviruses in 67.8% of the 90 samples, of group B rotaviruses in 10.0%, and of group C rotaviruses in 11.1%. In 11.1% of the samples, the presence of more than 11 bands suggested concurrent infection with more than 1 strain of rotavirus. In infections among nursing pigs, 76.4% were group A rotaviruses, 7.4% were group B, 7.4% were group C, and 8.8% were coinfections. In infections among weaned pigs, 40.9% were group A, 18.2% were group B, 22.7% were group C, and 18.2% were coinfections. Coelectrophoresis with prototype OSU and Gottfried strains revealed a great diversity in electropherotype among field strains of rotavirus.

Animals↗
PubMed1990

[Classification of retroviruses].

The retroviridae comprise a large number of viruses. In both nature and laboratories these viruses are associated with numerous diseases, including rapid or long latency malignancies, neurological disorders and immunodeficiency. The replication cycle is characterized by integration of the viral DNA into the host's genome after the reverse transcriptase copied the viral RNA into DNA. The discovery of human retroviruses had a late start. It was not until 1980 that the first oncovirus, the human T-leukaemia virus 1 (HTLV-1), was identified. The human immunodeficiency viruses (HIV-1 and HIV-2), belonging to the lentivirus subfamily, cause AIDS. Several simian virus, called simian immunodeficiency viruses (SIV) and related to HIV-1 and/or HIV-2 have been identified in monkeys and chimpanzees.

Animals↗
PubMed1996

Uveitis in dogs and cats: guidelines for the practitioner.

Uveitis is a commonly misdiagnosed ophthalmic condition with a wide aetiological base and often the cause cannot be established. Uveitis can be associated with systemic diseases like feline infectious peritonitis, feline immunodeficiency virus, feline leukaemia virus, lymphoma, toxoplasmosis and canine ehrlichiosis. The classification and general clinical signs of uveitis are discussed. Applicable clinical cases, manifestations and diagnostic methods of the selected diseases are mentioned, and a general approach to the treatment of uveitis is given.

Animals↗
PubMed1990

Oral hairy leukoplakia.

Oral hairy leukoplakia was first described in homosexual men infected with the human immunodeficiency virus. It is thought to be caused by infection with both the Epstein-Barr virus and human papillomavirus. We report 59 cases of oral hairy leukoplakia. The disease was diagnosed in patients in all risk groups and was categorized in all classes of the Walter Reed classification without significant differences in prevalence. Epstein-Barr virus could be demonstrated in all tissue samples examined; human papillomavirus was found in only a few specimens. In our series oral hairy leukoplakia had a chronic course, although temporary spontaneous healing occurred in some cases. Its appearance was a poor prognostic sign because acquired immunodeficiency syndrome developed in a significant proportion of patients within a few months of onset.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Antiviral medications.

As the numbers of identified viruses increase, it is expected that one of the classifications of medications receiving a great deal of attention is the antivirals. To understand the difficulty in developing these medications, the nurse must understand some of the basic principles underlying the way viruses develop, multiply, and cause disease. This article discusses some of those principles and presents the medications now available to treat viral diseases.

Antiviral Agents↗
PubMed1996

Molecular characterization of the Japanese encephalitis serocomplex of the flavivirus genus.

The Japanese encephalitis (JE) serocomplex of flaviviruses comprises 10 members, 9 of which: Alfuy (ALF); Koutango (KOU); Kokobera (KOK); Kunjin (KUN); Murray Valley encephalitis (MVE); JE; Stratford (STR); Usutu (USU); and West Nile (WN) have been isolated from Africa, southern Europe, Middle East, Asia, and Australia. The tenth member, St. Louis encephalitis (SLE) virus, is confined to North, Central, and South America. For ALF, KOK, KOU, STR, and USU, no sequence data have as yet been reported, and little molecular phylogeny has been determined for this complex as a whole. Using a rapid, one-step RT-PCR and universal primers, we have amplified and sequenced a 450-600 base pair region of the virus genome encompassing the N terminus of the nonstructural protein NS5 and the 5' end of the 3' noncoding region, for several strains of all of these viruses, except USU and SLE viruses. These data, as well as published sequence data for other flaviviruses, were analyzed with the ClustalW and Phylip computer packages. The resultant phylogenetic data were consistent with some of the current flavivirus serological classification, showing a close relationship between ALF and MVE viruses and between KOK and STR viruses, but suggested that KOK and STR are distantly related to the other viruses and should perhaps be reclassified in their own serocomplex. The data also confirmed the close relationship between KUN and WN viruses and showed that an isolate of KUN virus from Sarawak may represent a "link" between these two virus species. In addition, the primary sequence data revealed a polymorphic region just downstream of the stop codon in the 3' end of the viral genomes.

Amino Acid Sequence↗
PubMedDate not supplied

[Complexity analysis of genomes. I. Complexity and classification methods of detected structural regularities].

A new computer method for detecting local structural regularities in genomes of different microorganisms is described. The method is based on the concepts of complexity and complexity profile of a finite sequence. The complexity measure taking into account the specificity of genetic texts (presence of repeats, symmetries, inversions) is proposed. The genomes of different viruses and bacteriophages contained in Genbank were processed. The classification and interpretation of structural regularities were carried out.

Bacteriophages↗
PubMed2000

Molecular characterization of measles viruses isolated in Victoria, Australia, between 1973 and 1998.

Molecular epidemiology studies have made significant contributions to the control of measles virus infection through the identification of source and transmission pathways of the virus. These studies allow observation of changes in measles virus genotypes over time in a particular geographical location, clarification of epidemiological links during measles outbreaks, separation of indigenous strains from newly imported strains and distinction between vaccine- and wild-type virus-associated illness. A total of 35 wild-type measles viruses identified in Victoria, Australia, between 1973 and 1998 were characterized by nucleic acid sequence analysis of the nucleoprotein gene and, in some cases, the haemagglutinin gene. Relatedness between the viruses was studied and genotypes were assigned using a classification scheme recently proposed by the World Health Organization. Five recognized genotypes (C2, D1, D4, D5 and H) and one previously undescribed genotype, which we propose to be D7, were identified. Successive replacement of measles virus genetic lineages occurred in Victoria, with no evidence of temporal overlap, during this 25 year period. This pattern of circulation is likely to represent serial importation of wild-type measles virus strains from overseas foci of measles virus infections.

Adolescent↗
PubMed1993

Detection of Epstein-Barr virus nucleic acid sequences and protein in nodal T-cell lymphomas: relation between latent membrane protein-1 positivity and clinical course.

Forty-six nodal T-cell lymphomas, classified according to the updated Kiel classification, were investigated for the presence of Epstein-Barr virus (EBV) DNA by polymerase chain reaction (PCR), EBER 1 and 2 (EBER 1/2) and latent membrane protein-1 (LMP-1) expression. A combination of RNA in situ hybridization and immunohistochemistry was used to establish the phenotype of the Epstein-Barr virus harbouring cells. In 21 of 45 cases Epstein-Barr virus DNA sequences could be detected with the polymerase chain reaction. In 15 cases (14 of 21 EBV PCR positive cases), EBER 1/2 positive cells could be demonstrated. As judged by morphology, EBER 1/2 expression was found in nonneoplastic and neoplastic lymphoid cells. Double staining revealed that more than 80% of the EBER 1/2 harbouring cells, lacked B-, T- or histiocytic markers, suggesting down regulation of T- and B-cell markers by Epstein-Barr virus. In eight of 15 cases some EBER 1/2 positive T-cells (CD3, CD45RO, CD43) morphologically resembling tumour cells were found. In nine of 14 cases tested EBER 1/2 positive non-neoplastic B-cells (CD20) were seen. Based on in situ hybridization results, four patterns of EBER 1/2 positive cells were found, i.e. single cells (< 1 per medium power field (mpf), n = 3), scattered (1-25/mpf, n = 4), clustered (26-100/mpf, n = 5) and diffuse (> 100/mpf, n = 3). In eight of 15 cases a clustered or diffuse pattern of EBER 1/2 positive cells was found and these lymphomas were therefore considered to be strongly associated with Epstein-Barr virus. In these lymphomas LMP-1 expression was found to be associated with an aggressive clinical course and hepatosplenomegaly.

Herpesvirus 4, Human↗
PubMed2005

Mayaro virus: complete nucleotide sequence and phylogenetic relationships with other alphaviruses.

Mayaro (MAY) virus is a member of the genus Alphavirus in the family Togaviridae. Alphaviruses are distributed throughout the world and cause a wide range of diseases in humans and animals. Here, we determined the complete nucleotide sequence of MAY from a viral strain isolated from a French Guianese patient. The deduced MAY genome was 11,429 nucleotides in length, excluding the 5' cap nucleotide and 3' poly(A) tail. Nucleotide and amino acid homologies, as well as phylogenetic analyses of the obtained sequence confirmed that MAY is not a recombinant virus and belongs to the Semliki Forest complex according to the antigenic complex classification. Furthermore, analyses based on the E1 region revealed that MAY is closely related to Una virus, the only other South American virus clustering with the Old World viruses. On the basis of our results and of the alphaviruses diversity and pathogenicity, we suggest that alphaviruses may have an Old World origin.

Alphavirus↗
PubMed1994

A suggested taxonomy and nomenclature for the cricket paralysis and Drosophila C virus complex.

Biophysical, biological, and serological characters are presented which in combination allow isolates of cricket paralysis virus (CrPV) and Drosophila C virus (DCV) to be separated and seven distinct strains of CrPV to be defined. Reference isolates for CrPV and DCV are suggested along with a system of nomenclature that allows the passage history of a particular isolate to be easily described.

Animals↗