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Identification of an Epstein-Barr virus early gene encoding a second component of the restricted early antigen complex.

When the latent Epstein-Barr virus (EBV) genome in B95-8 cells is induced into a replicative phase, two abundant early RNAs are transcribed rightward from the EBV BamHI H DNA fragment into BamHI F. Analysis of cDNA clones prepared from the RNA of cells replicating EBV revealed that both RNAs contain the BHRF1 open reading frame. Part of BHRF1, cloned into a prokaryotic fusion protein expression vector, expressed a fusion protein in Escherichia coli and the purified fusion protein was used to generate a monoclonal antibody against BHRF1. This antibody was then employed to characterize the protein encoded by BHRF1 in cells replicating EBV. The monoclonal antibody reacted with a 17-kDa protein component of the restricted early antigen (EA) complex. The distribution of the protein in cells was similar to that noted when sera from patients with African Burkitt's lymphoma were used to stain these cells. The protein was synthesized before the major 47-56 kDa protein associated with the diffuse component of EA in superinfected Raji cells. All human sera containing antibodies to EA as determined by immunofluorescence (IF) reacted with the protein as did some sera determined to be anti-VCA positive and anti-EA negative by IF. The predicted amino acid sequence of the protein has characteristics which suggest that it is a membrane protein. It also has significant homology with both the anchor region of polyoma middle T antigen and with the predicted protein product of the bcl-2 mRNA activated by the 14/18 chromosome translocation characteristic of follicular lymphomas. This latter homology is extensive and colinear, suggesting common evolution and function. However, neither a mRNA which could efficiently translate the BHRF1 protein nor the BHRF1 protein could be detected in latently infected cells. Thus, the bcl-2 predicted protein is similar to an EBV protein synthesized in the early phase of virus infection.

Antibodies, Monoclonal↗

Lack of the expression of EBNA-2 and LMP-1 in T-cell neoplasms possessing Epstein-Barr virus.

We investigated 34 cases of T-cell neoplasm [15 cases of T-cell granular lymphocytic leukemia (T-GLL), 10 cases of T-cell non-Hodgkin's lymphoma (T-NHL), six cases of T-cell chronic lymphocytic leukemia (T-CLL), and three cases of cutaneous T-cell lymphoma] to study their association with Epstein-Barr virus (EBV). In 4 (three T-NHL and one T-GLL) of 34 cases, EBV genome was detected in a single episomal form, while polyclonal EBV-DNA was detected in one (T-NHL) of the remaining cases. All three cases of T-NHL having monoclonal EBV episome showed histologically diffuse large-cell lymphoma and developed leukemic conversion. Phenotypic analysis showed that two of these four cases were CD4+, CD8-, and the remaining two cases were CD4-, CD8+. The cells from all four cases were confirmed to be in T-cell lineage by detecting the rearrangement of T-cell receptor (TCR) beta or gamma chain gene. By reverse transcription-polymerase chain reaction (RT-PCR), EBNA-1 was detected at low levels, and neither EBNA-2 nor LMP-1 were found in any of the three cases examined. Lack of the expression of EBNA-2 and LMP-1 was also confirmed by immunocytochemical staining. The cells of these four cases did not show rearrangement or overexpression of c-myc and bcl-2 genes by Southern and Northern blots, and the mutation of p53 gene was detected in only one patient. These results suggest that other latent gene products of EBV or other cellular oncogenes are involved in the development of Japanese T-cell neoplasm after EBV infection.

Antigens, Viral↗

Accelerated appearance of multiple B cell lymphoma types in NFS/N mice congenic for ecotropic murine leukemia viruses.

Spontaneous lymphomas occur at high frequency in NFS x V+ mice, strains congenic for ecotropic murine leukemia virus (MuLV) proviral genes and expressing virus at high titer. In the present study, a total of 703 NFS x V+ lymphomas were studied by histopathology, immunophenotypic analysis, immunoglobulin heavy chain or T cell receptor beta chain rearrangements, and somatic ecotropic MuLV integrations; 90% of the lymphomas tested were of B cell lineage. Low-grade tumors included small lymphocytic, follicular, and splenic marginal zone lymphomas, while high-grade tumors comprised diffuse large-cell (centroblastic and immunoblastic types), splenic marginal zone, and lymphoblastic lymphomas. Comparison of mice of similar genetic background except for presence (NFS x V+) or absence (NFS x V-) of functional ecotropic MuLV genomes showed that NFS x V-clonal lymphomas developed at about one-half the rate of those occurring in NFS x V+ mice, and most were low-grade B cell lymphomas with extended latent periods. In NFS x V+ mice, clonal outgrowth, defined by Ig gene rearrangements, was associated with acquisition of somatic ecotropic proviral integrations, suggesting that, although generation of B cell clones can be virus independent, ecotropic virus may act to increase the rate of generation of clones and speed their evolution to lymphoma. The mechanism remains undefined, because only rare rearrangements were detected in several cellular loci previously associated with MuLV insertional mutagenesis.

Animals↗

Identification of a dimerization domain in the C-terminal segment of the IE110 transactivator protein from herpes simplex virus.

The 775-amino-acid IE110 (or ICP0) phosphoprotein of herpes simplex virus (HSV) functions as an accessory transcription factor during the lytic cycle and plays a critical role in reactivation from latent infection. By immunofluorescence analysis, IE110 localizes in a novel pattern consisting of several dozen spherical punctate granules in the nuclei of DNA-transfected cells. We constructed a hybrid version of IE110 that contained an epitope-tagged domain from the N terminus of the HSV IE175 protein and lacked the IE110 N-terminal domain that confers punctate characteristics. This hybrid IE175(N)/IE110(C) protein gave an irregular nuclear diffuse pattern on its own but was redistributed very efficiently into spherical punctate granules after cotransfection with the wild-type HSV-1 IE110 protein. Similar colocalization interactions occurred with internally deleted forms of IE110 that lacked the zinc finger region or large segments from the center of the protein, including both cytoplasmic and elongated punctate forms, but C-terminal truncated versions of IE110 did not interact. In all such interactions, the punctate phenotype was dominant. Evidence that C-terminal segments of IE110 could also form stable mixed-subunit oligomers in vitro was obtained by coimmunoprecipitation of in vitro-translated IE110 polypeptides with different-size hemagglutinin epitope-tagged forms of the protein. This occurred only when the two forms were cotranslated, not when they were simply mixed together. An in vitro-synthesized IE110 C-terminal polypeptide also gave immunoprecipitable homodimers and heterodimers when two different-size forms were cross-linked with glutaraldehyde and reacted specifically with a bacterial glutathione S-transferase/IE110 C-terminal protein in far-Western blotting experiments. The use of various N-terminal and C-terminal truncated forms of IE110 in the in vivo assays revealed that the outer boundaries of the interaction domain mapped between codons 617 and 711, although inclusion of adjacent codons on either side increased the efficiency severalfold in some assays. We conclude that the C-terminal region of IE110 contains a high-affinity self-interaction domain that leads to stable dimer and higher-order complex formation both in DNA-transfected cells and in in vitro assays. This segment of IE110 is highly conserved between HSV-1 and HSV-2 and appears to have the potential to play an important role in the interaction with the IE175 protein, as well as in correct intracellular localization, but it is not present in the equivalent proteins from varicella-zoster virus, pseudorabies virus, or equine abortion virus.

Animals↗

Research-based care on an acute inpatient psychiatric unit.

Many studies of research-based practice in nursing highlight factors that impede the development of practice. With the aim of adding to this body of knowledge, a modified grounded theory approach was used in order to understand more about these barriers and how individual nurses utilize research in their practice. A selective sample of five staff nurses from one acute inpatient psychiatric unit took part in semi-structured interviews. Three main themes were identified, each with two sub-themes. These were (a) activities to utilize research with (i) a 'systematic' model and (ii) a 'latent' model of research utilization (b) enhancing research utilization with (i) organizational culture and (ii) individual attitude and knowledge and (c) impeding research utilization with (i) resources (ii) resistance to change. It is suggested that for these nurses research utilization occurs through their individual knowledge, skill and motivation coupled with organizational commitment. Recommendation is made that further investigation of the 'systematic' and 'latent' models should be carried out. Additionally, it is suggested that these research findings might be used to inform future training, further research-based initiatives and to raise managerial awareness of the impeding factors of research utilization.

Acute Disease↗

Hypervirulent mutant of Mycobacterium tuberculosis resulting from disruption of the mce1 operon.

An estimated one-third of the world's population is latently infected with Mycobacterium tuberculosis, the etiologic agent of tuberculosis. Here, we demonstrate that, unlike wild-type M. tuberculosis, a strain of M. tuberculosis disrupted in the mce1 operon was unable to enter a stable persistent state of infection in mouse lungs. Instead, the mutant continued to replicate and killed the mice more rapidly than did the wild-type strain. Histological examination of mouse lungs infected with the mutant strain revealed diffusely organized granulomas with aberrant inflammatory cell migration. Murine macrophages infected ex vivo with the mutant strain were reduced in their ability to produce tumor necrosis factor alpha, IL-6, monocyte chemoattractant protein 1, and nitric oxide (NO), but not IL-4. The mce1 mutant strain complemented with the mce1 genes stimulated tumor necrosis factor alpha and NO production by murine macrophages at levels stimulated by the wild-type strain. These observations indicate that the mce1 operon mutant is unable to stimulate T helper 1-type immunity in mice. The hypervirulence of the mutant strain may have resulted from its inability to stimulate a proinflammatory response that would otherwise induce organized granuloma formation and control the infection without killing the organism. The mce1 operon of M. tuberculosis may be involved in modulating the host inflammatory response in such a way that the bacterium can enter a persistent state without being eliminated or causing disease in the host.

Animals↗

Lymphangioma-like Kaposi sarcoma.

BACKGROUND: Lymphangioma-like Kaposi's sarcoma (LLKS) is a rare morphologic expression of Kaposi's sarcoma (KS) that occurs in virtually all of the well-recognized clinical subtypes of the disease and has the potential to mimic other pathologic processes. In this study, we present the clinical and pathological features of four patients with LLKS. METHODS: Four cases of LLKS were retrieved from the dermatopathology files of our institution. All four tumours were tested immunohistochemically with anti-human herpesvirus-8 (HHV-8) latent nuclear antigen-1 (LNA-1) and anti-CD34 antibodies. RESULTS: Clinically, each patient presented with violaceous patches, papules or plaques; one patient presented with bullous lesions. All of the LLKS biopsy specimens revealed areas with characteristic light microscopic features of KS. Lymphangioma-like foci consisted of ectatic, irregularly shaped vascular spaces lined by mildly atypical endothelial cells. All tumour cells, including those associated with LLKS foci, showed a strong and diffuse reactivity for anti-HHV-8 LNA-1 and anti-CD34. KS progressed slowly in two patients with adequate follow-up. CONCLUSIONS: As LLKS can mimic other disease processes, the correct diagnosis relies heavily on the recognition of salient clinical and histological features of conventional KS, including a strong immunohistochemical expression of HHV-8-associated LNA-1 in lesional cells.

Adult↗

Lymphoproliferative disorders in rheumatoid arthritis patients on low-dose methotrexate.

Methotrexate is the most widely used second-line treatment in rheumatoid arthritis because of its excellent efficacy and safety profile. However, since 1991, about 100 cases of lymphoproliferative disorders have been reported in rheumatoid arthritis patients under methotrexate therapy. Four characteristics similar to those in lymphomas associated with immunodeficiency were identified during a review of the 48 cases for which detailed information is available. (1) Most cases were non-Hodgkin's B-cell lymphomas of the large cell or diffuse mixed type. (2) Extranodal involvement (55% of cases) was unusually common. (3) Evidence of Epstein-Barr infection was found in 46% of tested patients. (4) Of the 14 patients treated by methotrexate withdrawal alone, eight achieved a full remission, with follow-ups ranging from one to five years. These characteristics suggest a role for two factors: (1) the abnormalities in cell-mediated immunity seen in rheumatoid arthritis may promote latent Epstein-Barr virus infection, which may in turn lead to proliferation of malignant lymphoid cells; (2) the immunomodulatory effects of methotrexate may promote the development not only of opportunistic infections but also of Epstein-Barr virus-related lymphoproliferative disorders. There is no firm evidence to date that methotrexate has a direct oncogenic effect and no excess in malignant diseases has been reported with this drug. In conclusion, the rate of occurrence of lymphoproliferative disorders induced by low-dose methotrexate therapy remains controversial, although the characteristics of the malignancies and the possibility of a complete remission after methotrexate withdrawal militate against a chance association. Epidemiologic and other studies are needed to clarify this issue.

Adolescent↗

[Prostate-specific antigen: appropriate and inappropriate use].

PSA is a diffuse blood test, either for the follow-up of prostate cancer patients, or for the differential diagnosis of suspicious prostate lesions, or for "opportunistic" screening of healthy asymptomatic subjects. PSA is extremely useful in the two former instances, whereas screening is still in experimental phase: its efficacy in reducing prostate cancer mortality has not been demonstrated by ongoing studies which, on the contrary, have shown a relevant degree of "overdiagnosis" and "overtreatment" of "latent" carcinomas, which are not aggressive and would not have surfaced as symptomatic during lifetime. Screening should be banned from current practice until its efficacy is demonstrated, but bad and triumphalistic information by the media make a "prohibitionistic" approach rather impossible. If opportunistic screening can not be avoided, we should at least avoid too an aggressive diagnostic approach (e.g. random biopsy for borderline [4-10 ng/ml] PSA values).

Diagnosis, Differential↗

Ocular varicella-zoster virus infection in the guinea pig. A new in vivo model.

Corneal intrastromal inoculation of guinea pigs with approximately 10(4) plaque-forming units of live, adapted varicella-zoster virus (VZV) resulted in reproducible, acute, superficial corneal disease in all animals. The culture-positive VZV ocular infection progressed to involve 30% to 40% of the corneal surface in a diffuse punctate keratitis and 10% to 15% of this surface with microdendrites, characteristic of VZV-induced ocular disease. Retrograde dissemination of VZV to the trigeminal ganglia, midbrain, cerebellum, and superior cervical ganglia was demonstrated by whole-cell coculture VZV recovery. Central nervous system VZV dissemination, manifested by transient neurologic symptoms and pneumonitis, was evident in 60% of the animals. Varicella-zoster virus spread to the trigeminal ganglion during acute and early-latent infection was evident by electron microscopy.

Animals↗

The growth of human HIV-1 infected U937 cells in immune-deprived mice.

We report in vivo growth of human promonocytic cells infected with HIV-1 presented in new mouse model. Cloned U937 cells chronically infected with HIV-1 were grafted in (CBA*C57B1/6)F1 mice deprived of immunity by thymectomia and total body irradiation with subsequent marrow reconstitution. Nine weeks after cell inoculation, HIV-1-positive cells were found only in mice that received an additional single dose of cyclophosphamide (100 mg/kg bw) prior to transplantation, whereas, in mice without further immune deprivation, the complete elimination of cells bearing viral antigen occurred already on the seventh day after transplantation. The approach described may be suitable for in vivo development of antiviral drugs against latent infection in macrophage-like cells which represent a serious problem in therapy of AIDS in humans.

Animals↗

New human adenovirus (candidate adenovirus type 35) causing fatal disseminated infection in a renal transplant recipient.

An antigenically distinct adenovirus is described which was isolated in March 1973 from the lungs and kidney of a 61-year-old woman who died of diffuse interstitial adenovirus pneumonia 55 days after receiving a cadaveric renal allograft. Complement fixation, hemagglutination inhibition, and serum neutralization tests on sequential serum specimens from the patient confirmed that the adenovirus infection occurred in coincidence with her clinical illness and failed to document concomitant infection by any other common respiratory agent. Pathological and virological findings indicated that the pneumonia was only one manifestation of a disseminated adenovirus infection, the source of which may have been a latent infection pre-existing in the donor kidney. The adenovirus, purified by terminal dilution and plaque procedures, has antigenic, morphological, biological, biophysical, host susceptibility, and hemagglutinating properties characteristic of adenovirus group 1A. Buoyant densities in CsCl are 1.340 g/ml for the virion, 1,300 g/ml for the group complement-fixing (hexon) antigen, and 1.290 g/ml for the major soluble complete hemagglutinin (dodecon). The virus was serologically distinct from adenoviruses 1 to 34 in reciprocal serum neutralization tests with antisera to these viruses. We propose this virus as candidate adenovirus type 35 (holden).

Adenoviridae Infections↗

Detection of EBER nuclear RNA in T-cell lymphomas involving the skin--an in situ hybridization study.

To examine the relationship of Epstein-Barr virus (EBV) to cutaneous T-cell lymphoma (CTCL), a retrospective study was performed using formalin-fixed paraffin-embedded skin biopsies from 12 patients with cutaneous T-cell lymphoma. All cases were immunophenotyped with a panel of monoclonal antibodies including CD45RO, CD43, MB-2, CD20, and CD68. In situ hybridization studies to detect the EBV genome were performed, using the EBV-RNA probes for the early RNAs of EBV, namely EBER and BHLF. Among the 12 patients, six had primary CTCL, and six had secondary CTCL. The nasal cavity was the most frequent extracutaneous primary site. Immunophenotypically, all of the cases were of the T-cell lineage. In situ hybridization demonstrated a diffuse strong positive reaction for EBV transcripts (EBER) nuclear RNA in five out of 12 cases (41.7%) and a negative reaction for BHLF nuclear RNA probe in all the cases studied. Angiocentric lymphomas were positive in three out of the five cases (60%) studied. Secondary CTCL had a higher correlation with EBV than did primary CTCL, especially primary nasal T-cell lymphoma with subsequent cutaneous involvement. The EBV genome in lymphoma cells existed in a latently infected form but not in an actively replicating form. Three out of the five EBV-positive patients died, 8 months to 4 years after diagnosis. EBV infection alone in the lymphoma does not seem to affect the prognosis of CTCL patients significantly.

Adolescent↗

Malignant lymphoma of the adrenal gland: its possible correlation with the Epstein-Barr virus.

Initial manifestation of malignant lymphoma in the adrenal gland is a rare event, and clinical and pathologic features are not fully understood. We conducted a nationwide study in Japan, and 20 patients with malignant lymphoma that showed initial and main manifestation in the adrenal gland were identified. Clinical and pathologic findings were summarized. In addition, the presence of the Epstein-Barr virus (EBV) genome in the tumor cells was examined by using polymerase chain reaction (PCR) and in situ hybridization (ISH), together with the immunohistochemical evaluation of the expression of latent membrane protein-1 (LMP-1). There were 13 men and seven women; their ages at admission ranged from 40 to 87 years (median, 65 yr). Fever, anemia, and elevation of lactic dehydrogenase levels were the common presenting findings. One patient had acquired immunodeficiency syndrome. Adrenal tumors were bilateral in 15 patients and unilateral (all in the left site) in five. Prognosis was very poor; all but two patients died within 1 year after admission. Histologically diffuse large cell type was the commonest type (14 specimens). Immunohistologically, 16 specimens were B-cell type, and one was T-cell type. Another three specimens showing no positive reaction for any antibodies were also judged as B-cell type on purely morphologic grounds. Prominent intravascular proliferation of tumor cells was found in five patients. PCR for EBV genomes gave positive results in five patients; the virus was subtyped as A in three patients and as B in two. The ISH provided positive signals in nine samples, including all five specimens positive for PCR. Four of the nine cases with detectable EBV by PCR and/or ISH expressed LMP-1. The present study shows that adrenal lymphoma is EBV associated and has a B-cell phenotype.

Adrenal Gland Neoplasms↗

Nonactivatability of latent proteoglycanases in intact adult articular cartilage.

Para-aminophenylmercuric acetate activates collagenases and proteoglycanases in vitro only in cartilage plugs but not in intact articular cartilage. This suggests that activation of latent proteoglycanases is only possible after damage of the tissue's integrity. Therefore isolated plugs of cartilage seem not to be suitable for determining proteoglycan turnover. For these investigations we propose the use of intact joint areas from whole half-joints.

Animals↗

Immunoelectron microscopic localization of transforming growth factor beta 1 and latent transforming growth factor beta 1 binding protein in human gastrointestinal carcinomas: qualitative difference between cancer cells and stromal cells.

Transforming growth factor beta 1 (TGF-beta 1) is secreted as an inactive complex associated with latent TGF-beta 1 binding protein (LTBP). Tissue localization of these proteins has not been fully understood in human pathological conditions. We examined the immunohistochemical localization of TGF-beta 1 precursor (proTGF-beta 1) and LTBP in carcinomas and granulation tissue in the human gastrointestinal tract at the light and electron microscopic levels. In normal tissue, endothelial cells and granulocytes sporadically showed immunoreactivity for proTGF-beta 1, while epithelial cells were all negative. In cancer tissue, both cancer cells and stromal cells (fibroblasts, macrophages, and endothelial cells) were positive for proTGF-beta 1, more frequently in diffuse-type gastric carcinomas than in differentiated-type adenocarcinomas. Immunoelectron microscopy revealed that proTGF-beta 1 was localized in rough endoplasmic reticulum and perinuclear cisternae in fibroblasts, macrophages, and endothelial cells in cancer stroma and in fibrous granulation tissue. In contrast, the intracellular localization of proTGF-beta 1 in carcinoma cells was predominantly observed in the cytosol (cytoplasmic matrix). This finding suggests disarranged or blocked intracellular transportation of proTGF-beta 1 in cancer cells. The immunoreactivity for LTBP was not observed in the normal epithelial cells. It was localized in cancer stroma, not in cancer cells. Ultrastructurally, LTBP was located in the extracellular matrix around fibroblasts and smooth muscle cells. The intracellular immunoreactivity for LTBP was observed in rough endoplasmic reticulum of fibroblasts and smooth muscle cells, the same as in granulation tissue. These results suggest that gastrointestinal carcinoma cells produce no or a small amount of LTBP in vivo. Our investigation suggests that extensive fibrosis in both cancer stroma and granulation tissues may be promoted by TGF-beta 1 mainly secreted from stromal cells.

Carrier Proteins↗

Asbestos exposure. An update on pleuropulmonary hazards.

Asbestos exposure is causally related to the development of asbestosis, bronchogenic carcinoma, malignant mesothelioma, and nonmalignant pleural disorders. Clinical and roentgenographic manifestations of asbestosis mimic other diffuse fibrotic lung diseases. However, a concomitant finding of pleural plaques strongly suggests the diagnosis. The manifestations of bronchogenic carcinoma related to asbestos exposure are varied and do not differ from those unrelated to asbestos exposure. Malignant mesothelioma signals previous asbestos exposure. Nonmalignant pleural disorders may not cause any symptoms but should alert the physician to other concurrent or potential asbestos-related diseases. To diagnose asbestos-related diseases, physicians should bear in mind the long latent period and should take a careful, comprehensive occupational and environmental history. Cigarette smoking markedly increases the risk for development of bronchogenic carcinoma in asbestos workers and increases the mortality due to asbestosis.

Aged↗

Lymphoid neoplasms in HIV-positive individuals in India.

The HIV epidemic in the Asian subcontinent has a significant impact on India. Patients with AIDS have an increased risk of developing non-Hodgkin lymphoma (NHL). In this study, we have investigated the pattern of distribution of lymphoid neoplasms and also studied the Epstein-Barr virus (EBV)-association and p53 expression in 35 HIV-positive patients from India. The biopsy samples were studied for histology and for expression of CD20, CD3, CD15, CD30, light chains, CD138, bcl-6, epithelial membrane antigen, EBV-latent membrane protein-1, and p53 protein. In situ hybridization was performed with digoxigenin-labeled anti-sense EBV-encoded nuclear RNA-1 (EBER-1) probe. Polymerase chain reaction (PCR) was performed on DNA extracted from paraffin sections for EBV-subtype analysis. The 35 cases included 7 cases of Hodgkin disease (HD), 4 cases of plasmacytoma (PL), and 24 cases of NHL. Among the cases of NHL, 3 were Burkitt lymphoma (BL), 4 were diffuse large B-cell lymphoma (DLBL) of centroblastic type (CBL), 10 were DLBL of immunoblastic type (IBL), 4 were high-grade B-cell lymphoma (unspecified) and the rest were other subtypes. EBV-association was noted in all cases of HD, 2 of 3 BL, and 3 of 10 IBL. PCR analysis of the EBNA-3C gene revealed amplimers corresponding to type A. A p53 protein overexpression was noted in 6 of 10 IBLs, 1 of 3 BLs, 2 of 3 CBLs, and 5 of 7 cases of HD. This is the first reported study of lymphoid malignancies in HIV-positive individuals from India.

Adult↗