Truncated TSG101 transcripts in human leukemia and lymphoma cell lines

Inactivation of the TSG101 gene has been shown to induce cellular transformation of NIH3T3 fibroblasts, and aberrant TSG101 transcripts have been observed not only in various human solid tumors but also in hematopoietic malignant disorders. In the present study, we performed nested reverse transcription/polymerase chain reaction (RT-PCR) analysis to identify aberrant TSG101 transcripts in 43 human leukemia and lymphoma cell lines. We could detect only a single band of the wild-type transcript with the expected size in virtually all cell lines after the first round of PCR. As in the case with various human solid tumors, the smaller TSG101 transcripts appeared in most of these cell lines after the second round of PCR. Thus, the expression level of the variant transcripts was extremely low as compared with that of the wild-type transcript, and this finding was also confirmed by Northern blot analysis. Identification of various truncated transcripts with extensive deletions in the TSG101 coding region was confirmed by means of sequencing analysis, and expression of these transcripts did not appear to be associated with a specific type of hematopoietic malignant disorder. Southern blot analysis did not indicate any gross TSG101 gene rearrangement. The truncated transcripts were also detected in normal peripheral blood leukocytes. Our results suggest that the truncated TSG101 transcripts are definitely detectable in various human leukemia and lymphoma cell lines, but do not support the notion that the variant transcripts may have a major functional relevance in the pathogenesis of human hematopoietic malignant disorder.

Molecular cloning of a cDNA encoding mouse A15, a member of the transmembrane 4 superfamily, and its preferential expression in brain neurons

A15, a member of the transmembrane 4 superfamily (TM4SF), was isolated by differential screening of the cDNAs that are preferentially expressed on immature T cells. As a first step in the study of the biological function of the A15 molecule, we isolated cDNAs encoding the entire coding region of mouse A15. Nucleotide sequence analysis of the cDNAs revealed that mouse A15 shares 97% amino acid sequence identity with its human counterpart. The mouse A15 protein product has not yet been characterized, but is predicted to be 244 amino acids with four hydrophobic domains. Northern blot analysis of the RNA samples from various mouse tissues disclosed that the A15 transcripts are expressed most strongly in the brains, and are detectable in the colon, muscle, heart, kidney, and spleen. In situ hybridization of the mouse brain with ribo-probe established that the A15 transcripts are expressed primarily in neurons of the frontal cortex, olfactory bulb, dentate gyrus, caudoputamen, and CA3 region of the hypothalamus as well as in Purkinje cells in the cerebellar cortex, which strongly suggests that A15 may have a special function in the fundamental neuronal functioning of the higher nervous system.

Infrequent BCL10 mutations in B-cell non-Hodgkin's lymphomas

The BCL10 gene was recently isolated from the breakpoint region of t(1;14)(p22;q32) in mucosa-associated lymphoid tissue (MALT) lymphomas. Somatic mutations of BCL10 were found in not only t(1;14)-bearing MALT lymphomas, but also a wide range of other tumors. To clarify the actual frequency and spectrum of BCL10 mutations in primary B-cell non-Hodgkin's lymphomas (NHL), we examined a total of 139 NHL cases comprising 25 with MALT lymphomas, 54 with follicular B-cell lymphomas (FCL), and 60 with diffuse large B-cell lymphomas (DLBL). Polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) and sequencing analyses led to the identification of four nucleotide changes in FCL and one in DLBL. In contrast, no BCL10 mutations were found in our series of MALT lymphomas. While screening for mutations, we also found three polymorphic sequence variants at codons 5 and 213 and in intron 1 of the BCL10 gene. Our results strongly suggest that somatic mutations of BCL10, if they occur at all, are rare in B-cell NHLs and do not commonly contribute to their molecular pathogenesis.

Psychological impact of informed consent in hospitalized cancer patients. A sequential study of anxiety and depression using the hospital anxiety and depression scale

Patients with cancer receive an explanation of their disease and the recommended treatment when they are asked to give informed consent (IC). In the course of this process patients suffer severe distress, including anxiety and depression, but physicians tend to underestimate it. The goal of this study was to reveal the magnitude of such stress and any changes to this during the IC process by means of the Hospital Anxiety and Depression (HAD) scale, a self-assessment scale. Of 171 in-patients newly diagnosed with lung cancer, 119 were assessable for serial HAD scale scores on admission, immediately after the IC process, and at 1 and again at 2 weeks after the IC. Both anxiety and depression scores increased significantly immediately after IC. Female patients had significantly higher anxiety and depression scores than males at 1 week after the IC. The patients with poor performance status demonstrated high anxiety scores on admission and immediately after the IC, and substantial depression persisted longer in these patients. The prevalence of high scores of more than 11 (judged as adjustment disorder or more severe state) immediately after the IC was 50% for anxiety and 31% for depression. The prevalence decreased significantly within 1 or 2 weeks, but 41% and 14% of the patients still showed high anxiety and depression scores, respectively. Physicians should be aware of these facts and pay special attention to their patients' psychological distress in routine clinical practice.

Human aiolos, an ikaros-related zinc finger DNA binding protein: cDNA cloning, tissue expression pattern, and chromosomal mapping

The Ikaros gene (symbol ZNFN1A1) encodes the hematopoietic zinc finger DNA binding protein, which is now recognized as a central regulator of lymphoid differentiation and has been implicated in leukemogenesis. Recently, an Ikaros-related zinc finger protein, called Aiolos (ZNFN1A3), has been identified and characterized, thus establishing the presence of a gene family whose members may be hematopoietic transcription factors. Among Aiolos-mutant mice, development of B-cell lymphoma was frequently seen. As an initial approach to examining the possible involvement of Aiolos in the pathogenesis of human lymphoid proliferative disease, we isolated cDNA clones for human Aiolos from a B-cell cDNA library. The human Aiolos protein predicted from the cDNA sequence consists of 509 amino acid residues and shares 86% sequence identity with its mouse counterpart. As in the case with mouse Aiolos, no isoform for human Aiolos has been found. Northern blot analysis of various human tissues revealed that the Aiolos transcripts are expressed most strongly in peripheral blood leukocytes, the spleen, and the thymus, supporting the notion that Aiolos plays an important role in lymphoid lineages. Fluorescence in situ hybridization using a BAC clone established that the Aiolos gene is mapped to human chromosome band 17q11.2.

A novel gene, MALT1 at 18q21, is involved in t(11;18) (q21;q21) found in low-grade B-cell lymphoma of mucosa-associated lymphoid tissue

The t(11;18) (q21;q21) translocation is a characteristic chromosomal aberration in low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type. We previously identified a YAC clone y789F3, which includes the breakpoint at 18q21 in a MALT lymphoma patient. BAC and PAC contigs were constructed on the YAC, and BAC 193f9 was found to encompass the breakpoint region. In the present study, we further narrowed down the breakpoint region at 18q21 in five MALT lymphoma patients by means of FISH and Southern blot analyses using the plasmid contig constructed from BAC 193f9. The breakpoints at 18q21 in three of the five MALT lymphoma patients were found to be clustered approximately within the 20 kb region. By using exon amplification and cDNA library screening, we identified a novel cDNA spanning the breakpoint region that exhibited aberrant mRNA signals in four of the five MALT lymphoma patients. The nucleotide sequence predicted an 813 amino acid protein that shows significant sequence similarity to the CD22beta and laminin 5 alpha3b subunit. We refer to the gene encoding this transcript as MALT1 (Mucosa-Associated Lymphoid Tissue lymphoma translocation gene 1). The alteration of MALT1 by translocation strongly suggests that this gene plays an important role in the pathogenesis of MALT lymphoma.

[Analysis of the long-term survived patients with P-N2 non-small cell lung cancer]

We had 308 patients with P-N2 non-small cell lung cancer who were treated with pulmonary resection therapy from June 1975 to March 1994. We analysed 9 patients who could survive for 5 years and more after the operation. All of them were male and the mean age was 61.1 years. Histologically, 2 patients had adenocarcinoma and 7 patients had squamous cell carcinoma. The clinical staging was T2N1M0 in 2 patients, T1N2M0 in one, T2N2M0 in 2, T3N2M0 in 2, and T4N2M0 in 2 patients. The histopathological staging was T1 in one patient, T2 in 4, T3 in 3, and T4 in one patient. Three patients who had absolute non-curative operation (residual carcinoma on bronchial stump in 2 patients and residual mediastinal lymph nodes in one patient) were treated with radiation therapy after having operation. The one level mediastinal lymph node metastasis was found in 7 patients and multi-level one in 2 patients. Four patients out of nine are still alive and free from the cancer and 2 patients died of other unrelated disease. The patient who even have P-N2 non-small cell lung cancer with mediastinal lymph node involvement will live long after curative operation.

Selective usage of D-type cyclins in lymphoid malignancies

Three D-type cyclins, cyclin D1, D2 and D3, belong to the G1 cyclin, which regulates the G1/S transition of the cell cycle, and feature highly homologous amino acid sequences. The cyclin D1 gene was found to be transcriptionally activated in B-lymphoid malignancies with t(11;14), but available information is limited regarding expression of cyclin D2 and D3 in hematopoietic malignancies. We examined the expressions of three D-type cyclins to investigate how these homologous genes are differentially used. Northern blot hybridization with densitometric analyses was performed to examine 64 cell lines and 159 patients with various hematopoietic malignancies. Among lymphoid malignancies, cyclin D1 overexpression was exclusively detected in B cell malignancies accompanied by a genetic event consisting of 11q13 chromosomal translocation, consisting of 13 of 19 (68%) patients with mantle cell lymphoma, two of 11 (18%) with B-chronic lymphocytic leukemia, and one of six (17%) with multiple myeloma. The cyclin D2 expression was significantly higher in T cell malignancies than in B cell malignancies (P = 0.003 for cell lines and P < 0.0001 for patient samples, respectively). In the T cell malignancies, cyclin D2 overexpression was predominantly recognized in those with mature phenotype. Furthermore, cyclin D2 expression was upregulated by phytohemagglutinin (PHA) stimulation of normal T-lymphocytes, suggesting that this simply represents the proliferation status of mature T cells. Although cyclin D3 was ubiquitously expressed, its expression was reduced in lymphoid malignancies with cyclin D1 or D2 overexpression. In myeloid leukemias, although three D-type type cyclins were differentially expressed, no preference for particular D-type cyclins was found. This selective usage of D-type cyclins in lymphoid malignancies suggests an existence of a regulatory mechanism among three D-type cyclins.

Serum soluble Fas antigen in gastric MALT (mucosa-associated lymphoid tissue) lymphoma patients

We measured the serum level of soluble Fas (sFas) antigen in gastric MALT (mucosa-associated lymphoid tissue) lymphoma patients to investigate immune response of B lymphoma cells in gastric MALT lymphoma. The serum sFas antigen levels in 21 patients with Helicobacter pylori (HP)-positive MALT lymphoma were 4.51+/-0.25 (mean+/-SD) in the high grade malignant group (n=9) that demonstrated diffuse large cell (DL) components and 2.53+/-0.46 (mean+/-SD) in the low grade malignant group (n=12) that did not demonstrate DL components. Among 12 patients who underwent HP eradication therapy, the blood sFas antigen level lowered after eradication in 7 out of 10 patients who showed complete response or partial response, while sFas antigen level did not decrease in the 2 patients who showed no change or progression of the disease. In the high grade malignant group, 2 of 3 patients who underwent HP eradication treatment showed a mild decrease in the sFas antigen level as well as an improvement on endoscopic and histological examinations, but these sFas level were not normalized. The blood sFas antigen level tended to coincide with pathological activity and malignancy, suggesting that the sFas antigen level may be a prognostic indicator and useful index for the response of HP eradication treatment in gastric MALT lymphoma.

Spatiotemporal representation of binaural difference in time and intensity of sound in the guinea pig auditory cortex

Neural activity of the auditory cortex (AC) in response to a change of interaural intensity difference (IID) and interaural time difference (ITD) of sound stimuli was observed by optical recording with a 12 x 12 photodiode array and the voltage-sensitive dye, RH795. Guinea pigs (280-450 g) were anesthetized with sodium pentobarbital (30 mg/kg) and supplemental doses of neuroleptic solutions. When both ears were stimulated dichotically by tone bursts (14 kHz, 75 dB SPL), excitatory optical signals appeared in both anterior (A) and dorsocaudal (DC) fields of AC. An increase of intensity of ipsilateral stimulation from 65 to 95 dB SPL caused a decrease of neural activity of isofrequency bands in both fields. An increase of ipsilateral leads from -2.5 to 10 ms resulted in a gradual decrease of the amplitude of the excitatory responses. A strong inhibition was observed in field DC and the ventral portion of field A. These results show the different spatiotemporal representation of IID and ITD sensitivities in AC. However, the ipsilateral lead inducing a large inhibition was much longer than the time difference (80 micros) calculated from the interaural distance of the guinea pig. This indicates that the longer binaural inhibition observed in AC would have a different functional significance from that of the neural system of ITD detection in the guinea pig.

Determination of abundance and biovolume of bacteria in sediments by dual staining with 4',6-diamidino-2-phenylindole and acridine orange: relationship to dispersion treatment and sediment characteristics

We measured the abundance and biovolume of bacteria in intertidal sediments from Tokyo Bay, Japan, by using a dual-staining technique (4',6-diamidino-2-phenylindole and acridine orange) and several dispersion techniques (ultrasonic cleaner, ultrasonic sonicator, and tissue homogenizer). Dual staining reduced serious background fluorescence, particularly when used for silt-, clay-, and detritus-rich sediments, and allowed us to distinguish bacteria from other objects during both counting and sizing. Within the studied samples, the number of bacterial cells ranged from 0.20 x 10(9) to 3. 54 x 10(9) g of wet sediment(-1). With the cleaner and sonicator treatments, the bacterial numbers for all of the sites initially increased with dispersion time and then became constant. For the homogenizer treatments, the highest bacterial numbers were observed with the shortest (0.5- to 2-min) treatments, and the counts then declined steeply as the homogenization time increased, indicating that cell destruction occurred. The cleaner treatment had the possibility of insufficient dispersion of bacteria for fine-grain sediments. Within the studied samples, the bacterial biovolume ranged from 0.07 to 0.22 microm(3). With the cleaner and sonicator treatments, the biovolume peaked during the shorter dispersion time. This pattern was caused not by cell destruction but by the incremental portion of dispersed small cells. We concluded that with the cleaner and sonicator treatments, the longer dispersion time reflected the real size spectrum and was preferable for accurate estimation of mean bacterial biovolumes.

Ultraviolet A1 (340-400 nm) phototherapy for cutaneous T-cell lymphoma

BACKGROUND

The results of a recent study suggested that ultraviolet A1 radiation (UVA1R; 340-400 nm) phototherapy for atopic dermatitis works through induction of apoptosis in skin-infiltrating helper T cells, indicating the possibility that other helper T cell-mediated skin diseases may respond to UVA1R as well.

OBJECTIVE

The purpose of this open pilot study was to assess the therapeutic effectiveness of UVA1 phototherapy for cutaneous T-cell lymphoma (CTCL).

METHODS

UVA1 phototherapy was used as monotherapy in patients (n = 3) with histologically proven CTCL (stages IA and IB). For daily whole body UVA1 irradiations, either a high-dose (n = 2; 130 J/cm2 UVA1 per exposure) or medium-dose (n = 1; 60 J/cm2 UVA1) regimen was used. Therapeutic effectiveness was assessed clinically and histologically.

RESULTS

In each of the 3 patients, skin lesions began to resolve after only a few UVA1 radiation exposures. Complete clearance was observed between 16 and 20 exposures, regardless of whether the high- or medium-dose regimen had been employed.

CONCLUSION

These studies suggest that patients with CTCL stages IA and IB can be treated effectively with UVA1 phototherapy.

Human cysteine dioxygenase gene: structural organization, tissue-specific expression and downregulation by phorbol 12-myristate 13-acetate

The organization of the human cysteine dioxygenase (CDO) gene was found to be similar to its rat counterpart, and the location of the introns in the protein structure was identical to the rat CDO gene. The major transcription start site, identified by primer extension, was located 260 bp upstream from the ATG codon. The sequence of the 5'-immediate upstream region was highly conserved between the human and rat CDO genes. The putative promoter region contained a TATA-box-like sequence, and many putative cis-acting elements including HNF5, GRE, TRE, CRE, CArG box, ARE, MBS, and NF-kB. A Northern blot analysis revealed that CDO mRNA was strongly expressed in the liver and placenta, and weakly in the heart, brain and pancreas. CDO mRNA was also detected in human hepatoblastoma HepG2 cells. The CDO mRNA level in HepG2 cells was decreased after 2 h and reached a minimum 6 h-8 h after a phorbol 12-myristate 13-acetate (PMA) treatment, and then gradually returned to the basal level.

Cyclin D1/PRAD1/BCL-1 alternative transcript [B] protein product in B-lymphoid malignancies with t(11;14)(q13;q32) translocation

The cyclin-D1/PRAD1 oncogene, a key regulator of the G1-phase progression of the cell cycle, has been identified as the long-sought BCL-1 oncogene in B-cell malignancies with t(11;14)(q13;q32) translocation. A novel alternative spliced cyclin-D1 transcript, called transcript[b], has been identified. The level of the variant transcript[b] was lower than that of the originally reported cyclin-D1 transcript, called transcript[a], in several human non-lymphoid cancer cell lines but the endogenous cellular expression of transcript[b] products has not yet been determined. Northern-blot analysis and reverse-transcription-polymerase-chain-reaction (RT-PCR) analysis revealed that transcript[b] mRNA is well expressed in B-lymphoid cell lines with t(11;14)(q13;q32) translocation and at much lower or undetectable levels in other cells. Western-blot analysis using a human cyclin-D1-specific monoclonal antibody, which can recognize and distinguish the products of transcripts [a] and [b], strongly suggested that the transcript [b] protein is indeed expressed in these B-cell lines. The present study provides identification of the endogenous cellular expression of the cyclin-D1-transcript[b] protein and strongly suggests that this alternative form of cyclin D1 may play a significant role in the molecular pathogenesis of B-lymphoid malignancies with t(11;14)(q13;q32) translocation.

Synergistic effect of ubiquitin on lipopolysaccharide-induced TNF-alpha production in murine macrophage cell line RAW 264.7 cells

Ubiquitin synergistically augmented the production of tumor necrosis factor alpha (TNF-alpha) in the presence of lipopolysaccharide (LPS) in murine macrophage cell line RAW 264.7. To investigate the mechanism of this augmentation, we analyzed the effect of ubiquitin during TNF-alpha mRNA synthesis and degradation, and TNF-alpha degradation on RAW 264.7 cells stimulated by LPS. It is found that ubiquitin augmented TNF-alpha mRNA synthesis. Ubiquitin did not affect the degradation of TNF-alpha mRNA and TNF-alpha. In the presence of LPS, extracellular accumulation of TNF-alpha by ubiquitin was twice than those by LPS, but intracellular accumulation of TNF-alpha produced by ubiquitin with LPS or by LPS had no difference. These data indicate that ubiquitin might induce TNF-alpha accumulation mainly by up-regulation of the TNF-alpha gene transcription. Although extracellular functions of ubiquitin remain largely unknown, we postulate that ubiquitin might be involved in the modulatory mechanisms of immune response.

Significant role of laminin-1 in branching morphogenesis of mouse salivary epithelium cultured in basement membrane matrix

Mouse submandibular epithelium shows branching morphogenesis in mesenchyme-free conditions when covered with a basement membrane matrix (Matrigel) in medium supplemented with epidermal growth factor. In the present study, the role of laminin-1 (LN1), a major glycoprotein of Matrigel, in this culture system was defined. When the epithelium was cultured in a LN1-nidogen gel, the epithelium showed much branching, comparable to that observed with Matrigel. By electron microscopy, only a felt-like matrix was formed on the epithelial surface in the LN1-nidogen gel cultures, while an organized basal lamina structure was formed on the epithelial surface in direct or transfilter recombination cultures with mesenchyme. Next, the epithelium covered with Matrigel was cultured in medium containing either biologically active peptides from LN1, IKVAV-including peptide (2097-2108), AG10 (2183-2194), AG32 (2370-2381) or AG73 (2719-2730) from the alpha1 chain, or YIGSR-including peptide (926-933) from the beta1 chain. Only AG73 (RKRLQVQLSIRT from the alpha1 chain carboxyl-terminal globular domain) inhibited the epithelial branching in Matrigel. These results suggest that LN1-nidogen can support the branching morphogenesis of submandibular epithelium even if LN1-nidogen is not assembled into an intact basal lamina, and that the AG73 sequence is an important site on LN1, which interacts with submandibular epithelial cells.

Evaluation of endoscopic injection sclerotherapy with and without simultaneous ligation for the treatment of esophageal varices

For more effective and simple endoscopic injection sclerotherapy (EIS) for esophageal varices, we developed an EIS procedure with ligation (EISL) that is non-invasive, in which EIS and endoscopic variceal ligation (EVL) are performed simultaneously. In this study, we compared EISL and EIS in a randomized sample of patients (n = 14 for each procedure). For EISL, EVL was performed, including the injection site, after the injection of 5% ethanolamine oleate with iopamidol (EOI) into a varix. The mean number of treatment sessions required for eradication of esophageal varices was 2.3+/-0.5 for EISL and 3.9+/-0.8 for EIS (P < 0.001); the mean number of treatment sites was 6.2+/-2.2 for EISL and 14.0+/-5.0 for EIS (P < 0.001); the mean total amount of EOI used was 13.8+/-5.2ml for EISL and 26.3+/-9.8ml for EIS (P < 0.001). There were no significant differences in rates of recurrence of varices or in bleeding between the two groups. For EISL, fewer treatment sessions and less sclerosant were sufficient, probably because the sclerosants were more effective due to the blockage of variceal blood flow by the ligation. This method should provide a novel modification of EIS.

Molecular cytogenetic delineation of the breakpoint at 18q21.1 in low-grade B-cell lymphoma of mucosa-associated lymphoid tissue

Extranodal malignant non-Hodgkin lymphoma of mucosa-associated lymphoid tissue type (MALT lymphoma) represents a subtype of B-cell lymphoid malignancies with distinct clinicopathological features and is often associated with a favorable prognosis. Recent cytogenetic studies have revealed that t(11;18)(q21;q21) is a characteristic chromosomal aberration in low-grade B-cell MALT-type lymphoma. In the present study, we employed florescence in situ hybridization analysis using contiguous YAC clones mapped to the 18q21.1 region to identify a YAC clone, y789F3, encompassing the breakpoint of t(11;18)(q21;q21) in a MALT lymphoma. PI artificial chromosome (PAC) contigs constructed on this YAC clone were used to analyze the breakpoint region. PAC clone 264m4 was observed on normal chromosome 18 and on der(18), and PAC clone 879n 10 on normal chromosome 18 and on der(II), confirming that the breakpoint is located between these two PAC clones. We also found that a region of approximately 500 kb between the two PAC clones was deleted. These results indicate that the locus between PAC clones 264m4 and 879n 10 at 18q21.1 involved in t(11;18) translocation or associated deletion plays an important role in the development of MALT lymphoma.

Mechanisms involved in the regulation of key enzymes of cysteine metabolism in rat liver in vivo

Little is known about mechanisms of regulation of cysteine dioxygenase (CDO), gamma-glutamylcysteine synthetase (GCS), and cysteine-sulfinate decarboxylase (CSDC) in response to diet. Enzyme activity and Western and Northern or dot blot analyses were conducted on liver samples from rats fed a basal low-protein diet or diets with graded levels of protein or methionine for 2 wk. Higher levels of CDO activity and CDO protein but not of CDO mRNA were observed in liver of rats fed methionine or protein-supplemented diets, indicating that CDO activity is regulated by changes in enzyme concentration. Lower concentrations of the heavy or catalytic subunit of GCS (GCS-HS) mRNA and protein, as well as a lower activity state of GCS-HS in rats fed methionine- or protein-supplemented diets, indicated that dietary regulation of GCS occurs by both pretranslational and posttranslational mechanisms. Lower CSDC activity, CSDC protein concentration, and CSDC mRNA concentration were found in rats fed the highest level of protein, and regulation appeared to involve changes in mRNA concentration. Regulation of key enzymes of cysteine metabolism in response to diet determines the use of cysteine for synthesis of its essential metabolites.

Establishment of an inducible expression system of chimeric MLL-LTG9 protein and inhibition of Hox a7, Hox b7 and Hox c9 expression by MLL-LTG9 in 32Dcl3 cells

The MLL (HRX/ALL-1 gene is frequently disrupted in infantile leukemias and therapy-related leukemias and fused to various translocation partner genes. We previously showed that chimeric MLL proteins localize in the nuclei in a fashion similar to that of MLL protein even if the partner gene encodes a cytoplasmic protein and indicated the importance of the N-terminal portion of MLL common to various MLL translocations. This time we established an inducible expression system for chimeric MLL-LTG9 and truncated N-terminal MLL proteins (MLL-Zf(-)) in 32Dcl3 cells. By utilizing this system, we were able to show inhibition of Hox a7, Hox b7 and Hox c9 genes' expression by induced MLL-LTG9 and MLL-Zf(-). Up-regulation of Hox a7, Hox b7 and Hox c9 was observed when 32Dcl3 cells were cultured with granulocyte colony stimulating factor (G-CSF) in place of interleukin 3 and induction of MLL-LTG9 and MLL-Zf(-) was shown to suppress this upregulation. At the same time, expression of two mammalian Polycomb group genes, M33 and mel-18, which both reportedly affect Hox genes' expression, was not inhibited by MLL-LTG9 and MLL-Zf(-) induction. These results indicate that MLL has an important effect on the expression of at least some Hox genes in hematopoietic cells and suggest that inhibition of the proper expression of Hox genes by chimeric MLL proteins may dysregulate hematopoietic cell differentiation and proliferation, which then can lead to leukemogenesis.

[Superior vena cava reconstruction combined with resection of mediastinal-pulmonary malignant tumors]

From 1988 to 1997, we experienced 5 cases of the superior vena cava (SVC) replacement with expanded polytetrafluoroethylene (ePTFE) grafts combined with resection of mediastinal or pulmonary malignant tumors. Two patients had lung cancer and three had invasive thymoma. Resection and reconstruction of the superior vena cava (SVC) were performed by application of a bypass graft between the innominate vein and the right atrium in two cases and a temporary bypass using a heparin-coated tube in three cases. Except in one patient who died of acute respiratory failure, no complication or occlusive symptom were observed postoperatively. Two patients remain healthy for 5 years 4 months and 2 years 7 months after operation. Three died 9 years, 5 months, and 110 days after operation respectively. In conclusion, ePTFE graft replacement or patch angioplasty of the SVC should be part of planning and execution of radical excision with curative intent of mediastinal or pulmonary malignant tumors.

Expression and localization of cysteine dioxygenase mRNA in the liver, lung, and kidney of the rat

The expressions of cysteine dioxygenase (CDO) gene in the liver, lung, skeletal muscle, and kidney were studied by in situ hybridization with a cDNA probe from rat liver CDO under normal conditions. Significant expression of the CDO gene was detected in the liver, lung, and kidney, but not skeletal muscle. In the liver, the signal was confined to the cytoplasm of the hepatocytes. Furthermore, the signal was stronger in the periportal than that in the perivenous areas. In the lung, an intensive signal was found in the bronchiolar epithelium. As to the kidney, an intensive signal was observed in the distal convoluted tubules, while no signal was found in the proximal convultions.