Genealogy of families of SINEs in cetaceans and artiodactyls: the presence of a huge superfamily of tRNA(Glu)-derived families of SINEs

Several novel (sub)families of SINEs were isolated from the genomes of cetaceans and artiodactyls, and their sequences were determined. From comparisons of diagnostic nucleotides among the short interspersed repetitive elements (SINEs) in these (sub)families, we were able to draw the following conclusions. (1) After the divergence of the suborder Tylopoda (camels), the CHRS family of SINEs was newly created from tRNA(Glu) in a common ancestor of the lineages of the Suina (pigs and peccaries), Ruminantia (cows and deer), and Cetacea (whales and dolphins). (2) After divergence of the Suina lineage, the CHR-1 SINE and the CHR-2 SINE were generated successively in a common ancestor of ruminants, hippopotamuses, and cetaceans. (3) In the Ruminantia lineage, the Bov-tA SINE was generated by recombination between the CHR-2 SINE and Bov-A. (4) In the Suina lineage, the CHRS-S SINE was generated from the CHRS SINE. (5) In this latter lineage, the PRE-1 family of SINEs was created by insertion of part of the gene for tRNA(Arg) into the 5' region of the CHRS-S family. The distribution of a particular family of SINEs among species of artiodactyls and cetaceans confirmed the most recent conclusion for paraphyly of the order Artiodactyla. The present study also revealed that a newly created tRNA(Glu)-derived family of SINEs was subjected both to recombination with different units and to duplication of an internal sequence within a SINE unit to generate, during evolution, a huge superfamily of tRNA(Glu)-related families of SINEs that are now found in the genomes of artiodactyls and cetaceans.

Clinical, immunohistochemical and phenotypic features of aggressive nodal cytotoxic lymphomas, including alpha/beta, gamma/delta T-cell and natural killer cell types

Cytotoxic cells include natural killer (NK) cells and cytotoxic alpha beta and gamma delta T lymphocytes (CTLs). These cells express cytotoxic molecules of T-cell restricted intracellular antigen (TIA-1), and activated cytotoxic molecules of perforin, granzyme B, and FasL. Recent studies suggest that most extranodal T-cell lymphomas are derived from CTLs, and that NK cell lymphomas are extranodal. However, only a few nodal NK and cytotoxic lymphomas have been described so far. We present here the clinicopathological features of seven cases of nodal cytotoxic T and NK cell lymphomas. The study excluded anaplastic large-cell lymphomas expressing cytotoxic molecules. The neoplastic cells of all cases contained activated cytotoxic molecules of TIA-1, granzyme B, Fas ligand, and/or perforin. Phenotypically and genotypically, four cases showed alpha beta T cell type [CD2+, CD3+, T-cell receptor (TCR)-delta-1-, beta F1+, and TCR gene rearrangement], two cases showed gamma delta cell type [CD2+, CD3+, T-cell receptor (TCR) delta-1+, beta F1-, and TCR gene rearrangement], and one case showed NK cell type [CD2+, CD3-, CD56+, T-cell receptor (TCR) delta-1-, beta F1-, and TCR gene germline]. Using Southern blot analysis, Epstein-Barr virus (EBV) sequences were detected in six cases, and monoclonal terminal repeat proliferation was confirmed. In addition, in situ hybridization (ISH) studies for EBV showed EBV infection in almost all neoplastic cells. Clinically, all patients presented with peripheral lymphadenopathy in high clinical stages and showed an aggressive course. Hepatosplenomegaly was detected in six cases. During the course of the disease, bone marrow and extranodal invasion were noted in five cases. The nodal type showed an aggressive clinical course in all cases but one, as did the extranodal type. The nodal type varied in phenotype, but was closely associated with EBV infection.

Absence of cytotoxic molecules in CD8- and/or CD56-positive adult T-cell leukaemia/lymphoma

Adult T-cell leukaemia/lymphoma (ATLL) cells usually exhibit a CD4+ (helper/inducer) phenotype (CD4+/8-/56-), and only a minority of tumours express the CD8 (cytotoxic/suppressor) or CD56 (natural killer [NK]-associated) antigens. TIA-1 is a cytotoxic granule-associated protein expressed in NK cells and cytotoxic T lymphocytes (CTLs). Granzyme B, perforin and Fas ligand (FasL) are also expressed in activated CTLs and NK cells. To clarify the cytotoxic potential of ATLL cells, immunohistochemistry was performed in CD8+ and/or CD56+ ATLL cells, using anti-TIA-1, anti-granzyme B, anti-perforin and anti-FasL antibodies. We studied nine cases of CD8+ and/or CD56+ ATLL, all of which exhibited monoclonal integration of human T-cell leukaemia virus type 1 (HTLV-1) proviral DNA. Four cases exhibited a CD8+/CD56- phenotype, four others had a CD8-/CD56+ phenotype, and one was CD8+/CD56+. All but one case also expressed the surface antigens CD3, TCR alpha beta, and CD4. Expression of granzyme B and TIA-1 were demonstrated in three and two cases, respectively, but none expressed perforin or FasL. In the control study, 10 cases with typical CD3+/4+/8-/56- ATLL demonstrated no expression of those cytotoxic-associated proteins. Our findings suggest that CD8 and/or CD56 positivity probably confer(s) no cytotoxic function on ATLL cells, and it is possible that CD8 and CD56 may be simply aberrant surface markers in ATLL.

Seasonal variations in serotonin immunoreactivity and ultrastructure in the pineal organ of the Japanese grass lizard, with special reference to environmental temperature

The seasonal variations in serotonin immunoreactivity and ultrastructure of the secretory rudimentary photoreceptor cells (SRPC) were studied in the pineal organ of the Japanese grass lizard, Takydromus tachydromoides in relation to the environmental temperature. Our results clearly demonstrated that serotonin immunoreactivity in the lizard pineal organ displayed seasonal variations under an artificial photoperiod of LD 12:12 and natural temperature in the laboratory. Immunoreactivity became intense with increase in temperature from spring to summer, showing the strongest reaction in the summer, and subsequently became weak with the drop in temperature to winter. Also, the SRPC of the lizard showed distinct seasonal variations in number and size of the dense-cored vesicles correlated to the serotonin immunoreactivity. In contrast, the changes in size of the lysosomes and nucleoli of the SRPC were inversely proportional to that of the dense-cored vesicles. Furthermore, the lysosomes ingested some dense-cored vesicles after the autumn, and they coalesced to form huge autophagosomes or residual bodies during the winter. The present study provided serotonin-immunohistochemical and ultrastructural evidence for seasonal variations in the secretory activity of the lizard pineal organ in accordance with changes in the environmental temperature. However, there may be few functional relationships between the pineal gland and the reproductive organs in the male Japanese lizard in relation to environmental temperature.

Knock-out of the cyaY gene in Escherichia coli does not affect cellular iron content and sensitivity to oxidants

Friedreich ataxia is a recessively inherited neurodegenerative disease caused by deficiency of a highly conserved mitochondrial protein, frataxin. Frataxin deficiency results in mitochondrial iron accumulation and oxidative stress. Frataxin shows homology with the CyaY proteins of gamma-purple bacteria, whose function is unknown. We knocked out the CyaY gene in Escherichia coli MM383 by homologous recombination and we generated an E. coli MM383 strain overexpressing CyaY. Bacterial growth, iron content and survival after exposure to H2O2 did not differ among these strains, suggesting that, despite structural similarities, cyaY proteins in bacteria may have a different function from frataxin homologues in mitochondria.

Genetic analysis of sorted Hodgkin and Reed-Sternberg cells using comparative genomic hybridization

Hodgkin and Reed-Sternberg (H and RS) cells are generally considered to be the neoplastic cells of Hodgkin's disease (HD); however, such cells are found only in a minority of HD lesions. Very few data have so far been published on the cytogenetic abnormalities in HD. An analysis of unknown genetic aberrations has only recently become possible through the use of comparative genomic hybridization (CGH), which is based on the competitive binding of tumor and control DNA to metaphase chromosomes. In order to exclude the reaction of non-tumor cells, we used 100 sorted H-RS cells as the tumor DNA, then 100 sorted reactive T cells or B cells as the control DNA. We obtained the amplified DNA, using degenerate oligonucleotide-primed polymerase chain reaction (DOP-PCR). In addition, to confirm whether or not the lymphocytes in the background were reactive, we performed CGH with 100 sorted B cells and 100 sorted T cells. CGH was thus performed on 9 HDs, including 6 cases of mixed-cellularity (MC) sub-type and 3 cases of nodular-sclerosis (NS) sub-type. CGH of the B and T cells showed no genetic changes in any cases. In contrast, CGH of H-RS cells revealed both gains and losses of DNA in all 9 cases, and multiple changes were also observed. In situ hybridization showed an Epstein-Barr-virus infection in 5 cases of MC; however, no definite relationship was observed between the EBV infection and genetic changes. The most commonly observed genetic aberrations were a loss on 16q11/21 in 6 cases, a gain on 1p13 in 5 cases, and a gain on 7q35/36 in 5 cases. The large number of chromosomal alterations in HD suggests, therefore, that an increased degree of genetic instability play a role in the formation of H-RS cells.

Oversecretion of IL-18 in haemophagocytic lymphohistiocytosis: a novel marker of disease activity

We investigated the significance of interleukin (IL)-18 levels in the pathophysiology of haemophagocytic lymphohistiocytosis (HLH). IL-18 levels were significantly elevated in all nine patients with active HLH compared with those of healthy controls. Serial determination of IL-18 levels in three cases, showed a gradual decrease compared with those of IL-12, interferon (IFN)-gamma or soluble Fas ligand (sFasL) in the course of clinical improvement, and seemed to be elevated until complete disappearance of disease activity. IL-18 and IFN-gamma (CC 0.711, P = 0.018), and IFN-gamma and sFasL (CC 0.849, P = 0.0049) levels were significantly correlated. On the other hand, correlation between IL-12 and IFN-gamma, IL-18 and sFasL, or IL-18 and IL-12 was not observed. IL-18, IFN-gamma and sFasL levels significantly correlated with disease activity such as fever and alanine transaminase (ALT) levels. IL-18 mRNA expression was enhanced in spleen, but not in peripheral blood mononuclear cells (MNC), bone marrow MNC, liver from patients of active HLH, or the tumour from a patient with lymphoma-associated haemophagocytic syndrome (LAHS). These results suggest that IL-18 may play important roles in the pathogenesis of HLH, particularly through induction of Th1 cells. IL-18 measurement may be useful for the diagnosis and for the detection of smouldering disease activity.

Clinicopathological findings of virus-associated hemophagocytic syndrome in bone marrow: association with Epstein-Barr virus and apoptosis

Non-neoplastic hemophagocytic syndrome (HPS), also called virus-associated hemophagocytic syndrome (VAHS), has been thought to be a distinct clinical entity. A spontaneous recovery is common, but the prognosis of Epstein-Barr virus (EBV)-associated VAHS is poor. However, the role of EBV has yet to be clearly elucidated. A retrospective study of the bone marrow of 30 cases, in which the diagnosis of non-neoplastic VAHS was clinicopathologically confirmed, was performed. We were unable to histologically confirm the presence of neoplastic lesions, especially lymphoma cell infiltration. Ten of the patients were children (aged less than 15 years) and young adults (aged under 20 years; median age, 10 years). Twenty patients were adults (aged over 21 years; median age, 48 years). Twelve of these patients died, while 18 showed a spontaneous recovery. We performed immunological staining and in situ hybridization (ISH) for EBV. To clarify the presence of apoptosis, an in situ apoptosis detection (tunnel) method was used. In situ hydridization showed an EBV-presence in 16 of the 30 patients. In addition, the EBV-presence was confined in the lymphocytes, especially T lymphocytes in double stainings. The number of EBV-infected cells varied; however, the EBV presence was associated with ages. Nine of the 10 children and young adults showed an EBV-presence, while EBV was detected in seven of the 20 adults. Especially in 10 patients aged over 49 years, no EBV was detected. According to the in situ apoptosis detection, apoptotic cells were increased in number and considered to be lymphoid cells, but not myeloid or histiocytic cells. Some apoptotic cells were phagocyted with histiocytes. Histologically, apoptosis may be one of the factors that induced phagocytosis.

Expressions of cyclin E, A, and B1 in Hodgkin and Reed-Sternberg cells: not suppressed by cyclin-dependent kinase inhibitor p21 expression

p21 Is involved in the control of the mammalian cell cycle through the binding and inhibition of cyclin-dependent kinases. The cyclins are dependent on the phases of the cell cycle, and divided into two classes: mitotic cyclins (A, B1, B2) and G1 cyclins (C, D1, D2, D3, E). The product of the p21 gene is a potent downstream effector of the p53 tumor-suppressor gene function. The Hodgkin and Reed- Sternberg (H & RS) cells in Hodgkin's disease are reported to frequently express p53, p21, and nuclear proliferative activity (Ki-67). To clarify the relationship of p21, p53 and cyclins, we performed the immunohistochemistry of p53, p21, Ki-67, cyclin D1, cyclin E, cyclin A and cyclin B1, using 11 cases with Hodgkin's disease. In addition, we performed p53 gene sequencing of exon 5-8, and in situ hybridization of Epstein-Barr virus (EBV) EBER-1 region, whose products have reported to induce the expression of cyclin D. In this study, in all cases, Ki-67 was expressed in almost all H & RS cells, and p53 and p21 were expressed in H & RS cells. No p53 gene mutations were detected in any case, and p53 protein overexpression did not correlate with p53 gene mutations. The number of p21-positive H & RS cells was significantly related with that of the p53-positive cells. The cyclins E, A, B1 and D1 were also expressed in H & RS cells. Unexpectedly, the expression of the cyclins was not suppressed by p21 and p53 expression. In addition, the existence of EBV was not related to the expression of cyclins. It is considered that H & RS cells are, indeed, in cell cycle and commonly express the cell cyclins, and that the cell cycle of H & RS cells may not be specifically fixed in the G1, S, G2 or M phases.

Interferon-gamma prevents apoptosis in Epstein-Barr virus-infected natural killer cell leukemia in an autocrine fashion

The significant function of cytokines includes maintenance of cell survival as well as induction of cell differentiation and/or proliferation. We demonstrate here that interferon-gamma (IFN-gamma) plays a role for progression of Epstein-Barr virus (EBV)-infected natural killer cell leukemia (NK leukemia) through maintaining cell survival. NK leukemia cells obtained from 7 patients had clonal episomal forms of EBV, indicating that the leukemic cells were of clonal origin. Although normal NK cells constitutively expressed Bcl-2, the EBV-infected NK leukemia cells lacked endogenous Bcl-2 expression and were hypersensitive to apoptosis in vitro. The addition of IFN-gamma to the culture significantly inhibited their spontaneous apoptosis without inducing cell proliferation or upregulation of Bcl-2. The NK leukemia cells constitutively secreted IFN-gamma, and the patients' sera contained a high concentration of IFN-gamma, levels that were high enough to prevent NK leukemia cells from apoptosis. Bcl-XL was not involved in the IFN-gamma-induced NK leukemia cell survival. These data suggest that the acquisition of IFN-gamma-mediated autocrine survival signals, other than Bcl-2 or BCL-XL, might be important for the development of EBV-infected NK leukemia.

Restricted diversification of T-cells in chronic active Epstein-Barr virus infection: potential inclination to T-lymphoproliferative disease

To assess the abnormal T-cell expansion in chronic active Epstein-Barr virus infection (CAEBV), T-cell antigen receptor (TCR) repertoire was analyzed in four patients with the disease. All fulfilled the diagnostic criteria of CAEBV, presenting with fever, hepatosplenomegaly, cytopenia, abnormal high titers of anti EBV-antibodies, and positive EBV genome of unknown cause. Southern blotting probed with EBV-terminal repeats and TCR Cbeta gene indicated clonal expansion of the infected cells in 3 and 2 patients, respectively. The number of CD4+ HLA-DR+ cells appreciably increased in patients 1 (59%) and 2 (24%), who had a coronary aneurysm and central nervous system involvement, respectively. TCR gene expression examined by the inverse polymerase chain reaction methods revealed that Vbeta gene usages were preferential in all patients (Vbeta7 and Vbeta12: patient 1, Vbeta4: patient 2, Vbeta13: patients 3 and 4), compared with those in healthy controls. Valpha18 gene expression was remarkably high in patients 1 and 2. Moreover, Jbeta gene expression was skewing in the reigning Vbeta clones in all patients. Vbeta4-Jbeta1.5 and Vbeta13-Jbeta1.5 genes were clonally expressed in patients 2 and 4, respectively. These results suggest that CAEBV is associated with the restricted diversity of T-cells, which may stem from the sustained expansion of oligoclonal T-cells possibly driven by conventional viral antigens, but not, superantigens. Although the study is limited by the small number of patients, the unbalanced T-cell repertoire might contribute to the evolution of T-lymphoproliferative disease, otherwise, imply the innate defective immunity to EBV in CAEBV patients.

Basic fibroblast growth factor and fibrosis in Hodgkin's disease

Hodgkin's disease (HD) is characterized by the presence of Hodgkin and Reed-Sternberg (H-RS) cells against a hyperplastic background of reactive cells such as lymphocytes, histiocytes, plasma cells, eosinophils, neutrophils and stromal cells. In addition, the HD nodular sclerosis (NS) subtype shows characteristic fibrous bundles, while the other subtypes do not. The fibrosis is considered to correlate with multiple cytokines and cytokine networks. Basic fibroblast growth factor (bFGF), one of the potent stimulators of fibroblasts, has also been linked to the fibroproliferative process. To investigate the relationship of fibrosis and bFGF, we thus performed both immunostaining, in situ hybridization (ISH) and reverse transcriptase-polymerase chain reaction (RT-PCR) on 25 cases of HD, which included 12 cases with NS subtype, 10 cases with mixed cellularity (MC), and 3 cases with lymphocyte predominance (LP). In NS, the expression of bFGF was stronger than that in LP and MC. In addition, the H-RS cells in NS frequently expressed bFGF. The stromal cells and histiocytes in the background expressed bFGF in NS. However, in MC and LP the number of bFGF-expressed H-RS cells was small, and the bFGF expression of background cells was rarely detected. However, the amount of bFGF varied in each case with HD NS. The above results support the possibilities that H-RS cells and background cells are a cellular source of bFGF and that the bFGF expression of those cells is also one of the influencing factors in the development of fibrosis in the HD NS subtype.

A new multiple myeloma cell line, MEF-1, possesses cyclin D1 overexpression and the p53 mutation

BACKGROUND

The t(11;14)(q13;q32) translocation with cyclin D1 overexpression commonly is found in multiple myeloma (MM) and in mantle cell lymphoma (MCL). Several reports have shown that p53 mutations in MCL lead to blastoid transformation and a worse prognosis; however, the role of p53 mutations in MM with t(11;14) is unclear.

METHODS

In this study the authors describe a patient with MM with t(11;14) and a p53 mutation at presentation and characterized a cell line, MEF-1, established from this patient. Immunohistochemical analysis of p53 and cyclin D1 proteins was performed. The p53 gene was analyzed by polymerase chain reaction-single strand conformation polymorphism and direct sequencing. The expression of cyclin D1 mRNA was examined by Northern blot analysis.

RESULTS

MEF-1 had t(11;14) with overexpression of cyclin D1 mRNA and produced immunoglobulin kappa-light chain. MEF-1 had a mutation in exon 7 (codon 255-257) of the p53 gene, which was noted in the patient's myeloma cells.

CONCLUSIONS

p53 mutations may be important genetic events in disease progression of MM with t(11;14). The MEF-1 cell line may be a useful tool to study mechanisms of progression in MM based on abnormalities of the cyclin D1 gene.

Sticky DNA: self-association properties of long GAA.TTC repeats in R.R.Y triplex structures from Friedreich's ataxia

A novel DNA structure, sticky DNA, is described for lengths of (GAA.TTC)n found in intron 1 of the frataxin gene of Friedreich's ataxia patients. Sticky DNA is formed by the association of two purine.purine.pyrimidine (R.R.Y) triplexes in negatively supercoiled plasmids at neutral pH. An excellent correlation was found between the lengths of (GAA.TTC) (> 59 repeats): first, in FRDA patients, second, required to inhibit transcription in vivo and in vitro, and third, required to adopt the sticky conformation. Fourth, (GAAGGA.TCCTTC)65, also found in intron 1, does not form sticky DNA, inhibit transcription, or associate with the disease. Hence, R.R.Y triplexes and/or sticky DNA may be involved in the etiology of FRDA.

Ultrastructure and serotonin immunocytochemistry of the parietal-pineal complex in the Japanese grass lizard, Takydromus tachydromoides

The fine structure and immunocytochemical localization of serotonin in the cells of the receptor line were studied in the parietal eye and pineal organ proper of the Japanese grass lizard, Takydromus tachydromoides. Typical photoreceptor cells (PC) were the predominant cell type in the receptor line of the parietal eye, the outer segments of which had regular stacks of numerous disks similar to those of cones. The pineal organ contained relatively few PCs, which showed less well-developed outer segments than those of the parietal eye. In contrast, secretory rudimentary photoreceptor cells (SRPC) accounted for the majority of receptor cells in the pineal organ. These cells were structurally characterized by whorl-like lamellar outer segments and numerous dense-cored vesicles (80-280 nm in diameter). A small number of SRPC were also found in the parietal retina, which were similar to those in the pineal organ. In the parietal-pineal complex, numerous mitochondria located in the PC were larger and rounder than those in the SRPC. In the PC, basal processes prossessed only synaptic ribbons, whereas in the SRPC some of these processes contained synaptic ribbons and others contained dense-cored vesicles, rarely having both. Serotonin-immunoreactive cells were found not only in the pineal organ but also in the parietal eye, which closely resembled the cells of the receptor line in their size and shape. Furthermore, on immunoelectron microscopy for serotonin using the protein A-gold technique, gold particles indicating serotonin-immunoreactive sites were restricted in the core of dense-cored vesicles in the SRPC of the pineal organ. Regional differences in the distributions of the PC, SRPC and serotonin-immunoreactivity were found in the parietal-pineal complex.

Ultrastructural localization of acetylcholinesterase (AChE) activity in the chicken Harderian gland

Localization of acetylcholinesterase (AChE) was investigated in the chicken Harderian gland at the electron microscopic level. Nerve cells in the pterygopalatine ganglion showed AChE activity. They had a pale and large nucleus which was round or oval in shape. Reaction product of AChE was detected between the nuclear envelopes; in the cisterna of rough endoplasmic reticulum and the lumen of the Golgi lamellae, and on the plasma membrane of the nerve cell. In the interstitium of the gland, nerve fibers showing AChE activity were easily found. They were often seen in the perivascular space and between plasma cells. These nerve fibers had varicosities in contact with plasma cells and the endothelium or the smooth muscle fiber of the blood vessels. AChE-positive varicosities or terminals contained many small clear vesicles (about 50nm in diameter) and a few large dense-cored vesicles (about 100 nm in diameter). No contacts of nerve fibers with acinar cells or the ductal epithelium were observed in the present study. Our data indicate that cholinergic nerves play distinct roles in the regulation of the immune function of the chicken Harderian gland.

Discrimination of double primary lung cancer from intrapulmonary metastasis by p53 gene mutation

When multiple synchronous lung tumours are identified, discrimination of multicentric lung cancers from intrapulmonary metastases by clinical findings is often difficult. We used genetic alterations in p53 gene as a discrimination marker of double primary lung cancers from single lung cancer with intrapulmonary metastasis. Twenty of 861 patients with primary lung cancer who underwent lung resection were selected as subjects because they showed synchronous double solid tumours of the same histological type in the unilateral lung without distant metastases. In addition, they had been diagnosed as lung carcinoma with intrapulmonary metastasis by clinical and histological findings. DNAs were extracted from paraffin-embedded tissue of paired tumours from these 20 patients. Exons 5-9 of the p53 gene were examined for genetic alterations in the tumours by polymerase chain reaction, single-strand conformation polymorphism analysis and subsequent DNA sequencing analysis. Three different patterns in the distribution of p53 mutations in double lung tumours were observed: [A] mutation in only one of the tumours (four cases), [B] different mutations in the tumours (two cases), and [C] same mutation in both tumours (one case). The cases of [A] or [B] patterns could be classified as double primary lung cancers, while the case of the [C] pattern was suggested to be lung cancer with intrapulmonary metastasis. These results suggested that the multicentric cancers were more frequent than the intrapulmonary metastatic cancers in double cancer cases.

Nucleotide sequences of the cylindrical inclusion protein genes of two Japanese zucchini yellow mosaic virus isolates

The nucleotide sequences of the cylindrical inclusion protein (CIP) genes of two Japanese zucchini yellow mosaic virus (ZYMV) isolates (ZYMV-169 and ZYMV-M) were determined. The CIP genes of both isolates comprised 1902 nucleotides and encoded 634 amino acids containing consensus nucleotide binding motif. The sequence similarities between the two isolates at the nucleotide and amino acid levels were 91% and 98%, respectively. When the CIP gene sequences of the Japanese ZYMV isolates were compared with those of previously reported ZYMV isolates, the nucleotide and amino acid sequence similarities ranged between 81% and 97%, and between 95% and 97%, respectively. Phylogenetic analysis of the deduced amino acid sequences of the CIP genes indicated that the Japanese ZYMV isolates were closely related to those of other ZYMV isolates.

Accumulation of helper component/proteinase and coat protein of turnip mosaic virus in intact plants

The helper component/proteinase (HC/Pro) protein of turnip mosaic virus (TuMV) was fused with glutathione S-transferase (GST) and expressed as a fusion protein in Escherichia coli. The quality of antiserum raised against the GST-HC/Pro fusion protein was compared to that of antiserum raised against coat protein (CP) by image analyser. The result showed that these antisera were of similar quality. Then the both antisera were used to follow the time course of accumulation of HC/Pro protein and CP in intact TuMV-infected leaves. CP appeared first at day 3 post inoculation (p.i.) and gradually accumulated in uninoculated upper leaves, whereas HC/Pro protein appeared first at day 4 p.i., accumulated up to day 7 p.i. and then gradually decreased. Potyvirus proteins are encoded by a single translation unit spanning most of the genome and are presumably synthesized in equimolar ratios. Therefore, the reduced accumulation of HC/Pro protein in relation to CP at one month p.i. in infected plants is presumed to be the result of its degradation.

Jumping translocation of homogeneously staining region and tetraploidy with double minutes in acute myelomonocytic leukemia

We report a 71-year-old patient with acute myelomonocytic leukemia (AMMoL) who had complicated chromosomal abnormalities showing diploidy with a jumping translocation of a homogeneously staining region (hsr) and tetraploidy with double minutes (dmin). The analysis of gene amplification showed that hsr and dmin were the results of C-ETS 1 gene amplification. After induction chemotherapy, tetraploidy with dmin completely disappeared, while diploidy with hsr and del(11)(q23) remained until the patient died. It is speculated that hsr is more stable than dmin during chemotherapy and that the presence of tetraploidy is not necessarily a factor of poor response to chemotherapy for acute leukemia.

B-cell lymphoma of 708 cases in Japan: incidence rates and clinical prognosis according to the REAL classification

New insights into the pathogenesis of lymphoid malignancies have been gained through novel techniques such as genetic, molecular and immunologic methods. Recently, based on those findings, a new classification system for lymphoid malignancies, known as the REAL classification, has been proposed. To clarify the relation between the histological classification and prognosis of B-cell lymphoid malignancies, we re-classified 708 cases. In all cases, the B-cell phenotype and/or genotype was confirmed by immunohistochemical staining and/or receptor gene analysis. The most common B-cell lymphoma types were diffuse large B-cell lymphoma (58.8%), follicular lymphoma (12.1%), marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) (9.0%) and mantle cell lymphoma (5.9%). Minor types were lymphoblastic lymphoma (3.4%), Burkitt's lymphoma (2.4%), nodal marginal zone lymphoma (2.1%), lymphoplasmacytic lymphoma (2.0%) and plasmacytoma (1.4%). Rare types were prolymphocytic lymphoma and splenic marginal zone lymphoma. Using overall survival rates, the various B-cell lymphoma types could be divided into three broad groups for prognostic purposes: (1) the low risk group consisted of follicular lymphoma, marginal zone lymphoma of MALT, nodal marginal zone lymphoma, plasmacytoma and lymphoplasmacytic lymphoma; (2) the intermediate risk group consisted of diffuse large B-cell lymphoma, Burkitt's lymphoma and mantle cell lymphoma; and (3) the high risk group consisted of lymphoblastic lymphoma. In MALT, the low grade type had a better prognosis than the high grade type. In diffuse large B-cell lymphoma, the common type had a better prognosis than the variant type, which mainly consisted of the immunoblastic lymphoma. The histological classification will have a benefit for the clinical approach.

Expression and cellular localization of low-density lipoprotein receptor-related protein/alpha 2-macroglobulin receptor in human glioblastoma in vivo

Low-density lipoprotein receptor-related protein/alpha 2-macroglobulin receptor (LRP) has been proposed to mediate the cellular uptake and clearance of inactivated protease-inhibitor complexes in regulating proteinase activity at the cell surface, which is necessary for cellular migration and invasive processes. In this study, we investigated the presence of both LRP and urokinase-type plasminogen activator receptor (uPAR) in glioblastoma by reverse transcriptase-polymerase chain reaction (RT-PCR), and the cellular localization of LRP in glioblastoma tissues by immunohistochemical analysis. LRP mRNA was frequently expressed in glioblastomas and anaplastic astrocytomas compared with low-grade astrocytomas by RT-PCR analysis, and was well correlated with uPAR expression. The immunohistochemistry of LRP on sequential frozen sections showed that neoplastic glial cells and endothelial cells of glioblastomas exhibited intense LRP immunoreactivity, whereas LRP was almost undetectable in low-grade astrocytomas or in normal glial cells and endothelial cells of normal brain tissue. Glioblastomas from 11 patients in which the expression of LRP mRNA was observed by PCR displayed strong to moderate LRP immunoreactivity, with predominantly diffuse cytoplasmic and cell-surface localization. In normal brain tissues, LRP immunoreactivity was identified in the pyramidal neurons of the cerebral cortex. These results indicate that LRP is present both in the cellular cytoplasm and on the cell surface of glioblastomas with an increased expression of uPAR. Altered LRP expression might contribute to the stimulation of cell-surface proteolytic activity that in turn facilitates the invasiveness of glioblastoma in vivo.

CD95 (Fas) ligand expression of Epstein-Barr virus (EBV)-infected lymphocytes: a possible mechanism of immune evasion in chronic active EBV infection

The Epstein-Barr virus (EBV) induces infectious mononucleosis (IM) and can be associated with chronic active EBV infection (CAEBV). Cytotoxic T lymphocytes (CTL) play an important role in excluding EBV-infected cells. Two cytotoxic mechanisms of CTL have been demonstrated: one perforin/granzyme-based and the other Fas (CD95)/Fas ligand (FasL)-based. To clarify these two pathways in CAEBV, we analyzed six patients with CAEBV and four patients with IM using immunohistochemical staining of the lymph nodes. In both CAEBV and IM, CD8+ T-cells increased in number, but CD56+ natural killer cells were rare. In four of six cases with CAEBV, approximately half the lymphocytes were positive for T cell-restricted intracellular antigens (TIA-1), which were recognized by the cytolytic granules of CTL. In IM, the number of TIA-1 positive cells was smaller than that in CAEBV. Fas-positive lymphocytes were frequently encountered in both CAEBV and IM. However, FasL-positive lymphocytes increased in three of six patients with CAEBV, but not in patients with IM. Except for one case with CAEBV, the number of perforin- and/or granzyme-positive cells was small in number in both CAEBV and IM cases. In double-staining FasL and EBV in situ hybridization, FasL-positive EBV-infected lymphocytes were detected in CAEBV but not in IM. In CAEBV, the Fas/FasL pathway and not perforin pathways appears to play an important role in the pathogenesis. The data suggest that EBV-infected lymphocytes may evade immune attack through the expression of FasL.

Central nervous system T-cell lymphoproliferative disorder in a patient with chronic active Epstein-Barr virus infection

PURPOSE

Central nervous system (CNS)-T cell lymphoproliferative disorder (T-LPD) developing during the course of chronic active Epstein-Barr virus (CAEBV) infection is reported.

PATIENTS AND METHODS

CAEBV was diagnosed in a 14-month-old boy with fever, cytopenia, hepatosplenomegaly, and abnormal high titers of anti-Epstein-Barr virus (EBV) antibodies. At 8 years of age, he had a splenectomy because of progressive disease.

RESULTS

After 27 months of clinical remission, muscle weakness and paresthesia developed. Magnetic resonance imaging of his brain showed spotty T2 prolongation in left parietal, bilateral frontal, and temporal white matter with meningeal enhancement. Brain biopsy revealed the cerebral infiltration of CD3+, CD4+, CD8-, CD45RO+, CD56-, and EBV-encoded RNA 1+ cells.

CONCLUSIONS

The CNS involvement of EBV-associated T-LPD is a rare but serious complication in CAEBV without known underlying immunodeficiency.