Myosin light chain diphosphorylation is enhanced by growth promotion of cultured smooth muscle cells

The characteristics of actively growing smooth muscle cells (a variant, SM-3) were compared with those of growth-arrested cells with regard to response of myosin light chain (MLC) phosphorylation. Augmented MLC phosphorylation, in particular diphosphorylation, was observed in actively growing cells when stimulated with 30 microM prostaglandin F2alpha (PGF2alpha). The maximum level of diphosphorylation in growing cells was significantly higher than that in growth-arrested cells. The MLC diphosphorylation was sensitive to protein kinase C down-regulation by phorbol dibutylate and pretreatment by the protein kinase inhibitors, staurosporine (30 nM) and isoquinoline sulphonamide HA1077 (20 microM). The actively growing cells contained larger amounts of protein kinase C than growth-arrested cells. The phosphorylation sites of mono- and diphospho-MLC were determined to be MLC kinase-dependent sites (Thr18, Ser19). The PGF2alpha concentration/response curves of MLC diphosphorylation were shifted to the left and upwards in the presence of the protein phosphatase inhibitor calyculin A. These results suggest that PGF2alpha stimulation of actively growing SM-3 cells augments MLC kinase-dependent MLC diphosphorylation. Protein kinase C is involved indirectly in this reaction, possibly through MLC phosphatase-sensitive regulatory mechanisms.

Translocation (9;11;22)(p22;q23;q11). A new type of complex variant translocation of t(9;11)(p22;q23) with MLL rearrangement

We describe a patient with acute monocytic leukemia (M5a, FAB classification) associated with a new type of variant translocation (9;11). Southern blot analysis showed the rearrangement of the MLL (ALL-1/HRX) gene at 11q23. Fluorescence in situ hybridization (FISH) with painting probes of chromosomes 9, 11, and 22 revealed the translocation as t(9;11;22) (p22;q23;q11). This is more evidence that the production of chimeric mRNA following the translocation of the LTG9 (MLLT3/AF9) gene at 9p22 to 11q is a critical event in this leukemia subtype.

Selectivity of action of staurosporine on Ca2+ movements and contractions in vascular smooth muscles

We examined the effects of staurosporine, a protein kinase inhibitor, on Ca2+ movements and contractions due to KCl and 12-deoxyphorbol 13-isobutyrate (DPB), which are thought to activate myosin light chain kinase and protein kinase C, respectively. In rabbit aortae, staurosporine inhibited contractions due to KCl (65.4 mM) and DPB (1 mu M) with IC50 values of 140.5 +/- 1.3 nM and 13.3 +/- 1.3 nM, respectively. Calphostin C, a putative inhibitor of protein kinase C, inhibited DPB-induced contraction with much less effect on the KCl-induced one. On the other hand, wortmannin, an inhibitor of myosin light chain kinase, was 4 times more potent on KCl-induced contraction than the DPB-induced one. Staurosporine at 100 nM decreased the rise in cytosolic Ca2+ due to KCl, whereas wortmannin did not affect it. In rabbit cerebral arteries permeabilized with beta-escin, staurosporine at 100 nM, but not 30 nM, inhibited Ca2+ -induced contraction in the presence of 1 mM ATP. The results indicate that staurosporine preferentially inhibits a contraction dependent on protein kinase C than that dependent on myosin light chain kinase in vascular smooth muscles. Its ability to inhibit KCl-induced contraction involves inhibition of voltage-dependent Ca2+ channels.

Cloning and expression of a murine cDNA homologous to the human RCK/P54, a lymphoma-linked chromosomal translocation junction gene on 11q23

The RCK/P54 gene was previously isolated from the chromosome translocation breakpoint region on 11q23 of a human lymphoma cell line, RC-K8, with t(11;14)(q23;q32). It was found to encode a 472-483-amino-acid (aa) polypeptide belonging to an RNA helicase/translation initiation factor family. The aim of the present investigation was the isolation and comparative sequence analysis of the mouse RCK/P54 cDNA from a BALB/c spleen cDNA library. Sequence analysis revealed an open reading frame (ORF) predicting a polypeptide of 483 aa showing 97.7% identity to human RCK/p54. Northern analysis demonstrated a 7.5-kb signal in all tissues tested and in vitro translation analysis showed a 54-kDa polypeptide. These results indicate that both mouse and human RCK/P54 are highly conserved.

Experimental neonatal autoimmune myasthenia gravis: an immunohistochemical, ultrastructural and electrophysiological study of the motor end-plate

Neonatal rats born of and nursed by mothers immunized with Narke japonica acetylcholine receptor protein had elevated serum anti-acetylcholine receptor antibodies that reached the mother's level on day 10 after delivery and decreased rapidly after weaning. IgG was present at the motor end-plates up to day 170, and the motor end-plate fine structure remained abnormal up to day 80. Miniature end-plate potential amplitudes in the diaphragm were at the control levels within 10 days of birth, but were lower than those of the controls up to day 80 after birth. We could not obtain the direct evidence that transient synthesis of antibodies occurs in experimental autoimmune myasthenia gravis pups. This model can serve as an experimental model of transient neonatal myasthenia gravis in humans, exception for the route of antibody transfer and the time of the onset of illness.

The positive nuclear staining observed with monoclonal antibody against PRAD1/cyclin D1 correlates with mRNA expression in mantle cell lymphoma

Recently, we produced a monoclonal antibody, 5D4, against the PRAD1/cyclin D1 product and suggested positive nuclear staining to be associated with mantle cell lymphoma (MCL). Now we have further characterized the specificity of this antibody and studied the relation of immunohistochemical detection to PRAD1/cyclin D1 mRNA expression and DNA rearrangement. Immunofluorescence and immunoblotting studies demonstrated the 5D4 antibody to be crossreactive with cyclin D2, but not cyclin D3. On immunostaining, 15 of 19 MCL cases (79%) presented the nuclear staining pattern and PRAD1/cyclin D1 mRNA expression was detected by Northern blot analysis in 12 of 15 MCL cases studied (80%): all cases with the mRNA expression showed the nuclear staining pattern. Southern blot analysis with 11q13 BCL-1 probes detected DNA rearrangements in 8 of 19 MCL cases (42%), all 8 exhibiting PRAD1/cyclin D1 mRNA expression. In 21 lymphoma cases of types other than MCL, neither the mRNA expression nor the nuclear staining were observed, although cytoplasmic staining was often apparent. These results indicated that positive nuclear staining of lymphoma cells by 5D4 antibody reflects PRAD1/cyclin D1 mRNA expression, and showed that this monoclonal antibody has diagnostic value for differentiating MCL from other types of lymphomas.

The time course of myosin light-chain phosphorylation in blood-induced vasospasm

The phosphorylation of an M(r) 20,000 myosin light chain (MLC20) promotes the generation of contractile force through actin-myosin adenosine triphosphatase in most agonist-mediated vascular smooth muscle cell contraction. However, the role of calcium-mediated contractile processes in sustained arterial narrowing after subarachnoid hemorrhage remains unknown. In a femoral artery model of vasospasm, whole blood was applied to arteries in 54 rats for periods of 2 to 10 days; the contralateral artery treated with platelet-rich plasma served as matched control. During the early stage of vasospasm (Days 2-5), in the media of arteries exposed to blood, MLC20 phosphorylation (including diphosphorylated forms) increased significantly (30-38%; P < 0.05); total medial MLC20 during this interval was comparable to that in controls. After 5 days, however, total MLC20 decreased markedly (> 90%; P < 0.01) compared with controls; phosphorylated MLC20 was undetectable during this interval. MLC20-mediated contractile processes may be prominent in the early stages of arterial narrowing after subarachnoid hemorrhage; later stages are associated with the loss of MLC20 and the possible persistence of arterial narrowing by other mechanisms.

Thermal conditions in the bathroom in winter and summer, and physiological responses of the elderly during bathing

Thermal conditions in the bathroom and physiological responses were examined during winter and summer. The subjects were 22 male and 20 female elderly people, between 65 and 88 years old living in 25 houses in Gunma Prefecture, Japan. Heart rate, blood pressure, skin temperature and thermal sensation were measured during bathing. Changes in thermal sensation due to bathing were assessed in the living room and dressing room on a 9-point scale. Then they were asked about the purposes of bathing and the facilities of bathroom and dressing room. The results are summarized as follows: 1. The purpose of bathing in winter was to warm up for more than 80% of the subjects. In summer, all subjects felt refreshed by bathing. Eighty-five percent of the subjects took a bath every other day in both seasons. 2. Fifty-two percent of the bathrooms had no ventilating fans and 32% had no exclusive dressing rooms. 3. The average room temperature in the dressing rooms was 13-14 degrees C in winter. Thermal sensation was 'cool', 'slightly cold' or 'cold' for more than two-thirds of the subjects when they were partially nude, and there were no heaters in most dressing rooms. 4. The heart rate increased steadily, and reached a maximum value in a partially dressed condition in both seasons. 5. In winter, a marked increase of systolic blood pressure was observed in the partially nude condition. There was a significant difference between the before bathing condition and partially nude condition in winter.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular features of the CAG repeats and clinical manifestation of Machado-Joseph disease

Machado--Joseph disease (MJD) is an autosomal dominant spinocerebellar degeneration mapped to chromosome 14q32.1. The CAG expansions of the MJD1 gene was identified as the cause of the disease. We have analyzed 90 MJD individuals from 62 independent MJD families and found that the MJD1 repeat length is inversely correlated with the age of onset (r = -0.87). The MJD chromosomes contained 61-84 repeat units, whereas normal chromosomes displayed 14-34 repeats. In the normal chromosomes, 14 repeat units were the most common and the shortest. In association with the clinical anticipation of the disease, a parent--child analysis showed the unidirectional expansion of CAG repeats and no case of diminution in the affected family. The differences in CAG repeat length between parent and child and between siblings are greater in paternal transmission than in maternal transmission. Detailed analysis revealed that a large degree of expansion was associated with a shorter length of MJD1 gene in paternal transmission. On the other hand, the increments of increase were similar for shorter and longer expansion in maternal transmission. Among the three clinical subtypes, type I of MJD, with dystonia, showed a larger degree of expansion in CAG repeats of the gene and younger ages of onset than the other types.

Selective inhibition of myosin phosphorylation and tension of hyperplastic arteries by the kinase inhibitor HA1077

To examine possible alterations in myosin light chain phosphorylation in hyperplastic arteries, rabbit strips from right hyperplastic and left normal control carotid arteries were used for experiments 6 weeks after the ballooning procedure. When the hyperplastic artery was stimulated with various concentrations of K+ (10, 20, 30, 40 and 60 mM), the maximal tension in response to each concentration was significantly higher (P < 0.05) than that in the control artery. The maximal extent of myosin light chain phosphorylation induced by 60 mM K+ in the hyperplastic artery was also significantly higher than that in the control (55.1 +/- 4.1 vs. 45.1 +/- 3.2%, mean +/- S.D.). However, the [Ca2+]i response to elevated K+ in hyperplastic arteries was much the same as that in control arteries, when measured with fura-PE3. HA1077 (1-5-(isoquinolinesulfonyl)-homopiperazine), a protein kinase inhibitor, was about 3-5 times more effective in inhibiting the tension and myosin light chain phosphorylation induced by 60 mM K+ in the hyperplastic artery than in the control artery. Nifedipine inhibited the tension and myosin light chain phosphorylation to the same extent in control and hyperplastic arteries. Thus, an alteration of the myosin light chain phosphorylation system, but not an alteration of Ca2+ mobilization, may be involved in the enhanced contraction of the hyperplastic artery. The enhanced phosphorylation of myosin light chain may be sensitive to HA1077.

Immunohistochemical analysis of cyclin D1 protein in hematopoietic neoplasms with special reference to mantle cell lymphoma

Immunohistochemical expression of PRAD1/cyclin D1 protein has been investigated in 106 tissue specimens of 104 cases of lymphoma, non-neoplastic lymphoid disorders and other hematologic malignancies by employing the monoclonal antibody 5D4 with formalin-fixed paraffin-embedded sections, using the microwave oven heating method. Positive neoplastic cells were found in 60 (74%) of 81 cases of non-Hodgkin's lymphoma. The positivity pattern was nuclear in 17 (85%) of 20 cases of mantle cell lymphoma in which cytoplasmic staining was also seen. This pattern of cyclin D1 positivity was in contrast to the negative staining of normal reactive mantle zones. In the other cases, positivity appeared to lie within the cell cytoplasm without nuclear staining, and most of the nodal follicular and diffuse B-cell lymphomas variously expressed PRAD1/cyclin D1. In contrast, the reaction was absent in a significant number of T-cell and extranodal B-cell lymphomas. Immunolocalization of PRAD1/cyclin D1 expression appears to be a useful diagnostic adjunct to discriminate mantle cell lymphoma from other non-Hodgkin's lymphomas.

Phosphorylation of calponin by PKC is blocked by F-actin in vitro

Polyclonal antibody against phosphorylated calponin was raised in rabbits by application of the peptide corresponding to residues 183-195 of calponin phosphorylated by protein kinase C. When calponin was incubated with protein kinase C, only free calponin was recognized by this antibody and calponin of native thin filament or that binding to F-actin did not. In experiments done using [gamma-32P] ATP, no radioactivity was detected except for free calponin. Calponin phosphorylation was suppressed in an actin dose-dependent manner and the phosphorylation of calponin was completely blocked when the actin molar ratio to calponin exceeded 10. These data suggest that phosphorylation of calponin by protein kinase C was apparently blocked by F-actin.

Monoclonal antibody against PRAD1/cyclin D1 stains nuclei of tumor cells with translocation or amplification at BCL-1 locus

Mouse monoclonal antibodies were produced against the bacterial product encoded by human PRAD1/cyclin D1 gene, which is known to be involved in tumors with translocation or amplification at BCL-1 locus of 11q13. The immunizing antigens used were GST-PRAD1 and T7 gene 10-PRAD1 fusion products. Four antibodies were reactive with both PRAD1 fusion products and cell lysates of B-cell tumor cell lines with t(11;14)(q13;q32) and a breast cancer cell line with 11q13 amplification, on immunoblotting. An immunofluorescence study showed that only one of them stained nuclei of cells with 11q13 abnormalities. Since this antibody proved applicable for conventional paraffin-embedded tissue sections, immunohistologic staining of various lymphoma tissues was performed. Eight of 11 mantle cell lymphomas showed intermediate to strong positivity and 6 of the positive cases demonstrated characteristic staining patterns that were either predominantly nuclear or both nuclear and cytoplasmic. The nuclear staining pattern was not observed with other types of lymphoma and thus may correlate with PRAD1 mRNA overexpression.

A variant chromosome translocation at 11q13 identifying PRAD1/cyclin D1 as the BCL-1 gene

The 11q13 breakpoint region of t(11;14) (q13;q32), translocated to the Ig heavy chain locus at 14q32, has been designated as BCL-1 for B-cell leukemia/lymphoma-1, but the nature of the transcriptional unit has long remained unclear. Recently, the PRAD1 gene encoding cyclin D1, isolated from the 11q13 region, was proposed as a candidate BCL-1 gene on the basis of chromosome walking and concordant overexpression of PRAD1 mRNA in cell lines with t(11;14)(q13;q32). We report here molecular analysis of a variant translocation at the BCL-1 locus, t(11;22)(q13;q11), showing juxtaposition of the Ig light chain gene, Ig lambda, to the PRAD1 gene at its 3' end, resulting in overexpression of PRAD1 mRNA. Because only the PRAD1 gene is present between the Ig heavy chain and light chain gene breakpoints, an identity between BCL-1 and the PRAD1/cyclin D1 gene is strongly indicated.

Acute myelomonocytic leukemia after treatment with chronic oral etoposide: are MLL and LTG9 genes targets for etoposide?

A patient with secondary acute myelomonocytic leukemia after treatment with chronic oral etoposide (VP-16) for lung cancer is reported. The leukemic cells showed a t(9;11)(p22;q23) translocation. Southern blot analysis revealed the rearrangement of the MLL (ALL-1/HRX) gene at 11q23. Reverse transcriptase-polymerase chain reaction (RT-PCR) revealed a chimeric mRNA between the MLL gene at 11q23 and LTG9 (MLLT3/AF-9) gene at 9p22. The patient was successfully treated with a VP-16 based regimen. This case is instructive in the understanding of the leukemogenesis of VP-16-related leukemias.

Prevention of TCR-mediated apoptosis by the elevation of cAMP

The stimulation through TCR-CD3 complexes by immobilized anti-CD3 antibody induced the production of IL-2 and activation-induced cell death (ACD) in the majority of T cell hybridomas. However, some hybridomas produced IL-2 without showing any signs of ACD by the same stimulation, indicating that TCR-CD3-mediated signaling pathways of IL-2 production and of ACD are different. These pathways were discriminated from each other by protein kinase inhibitors and cAMP-elevating reagents such as forskolin. The pathway of IL-2 production but not of ACD was inhibited by protein kinase inhibitors. On the other hand, various cAMP-elevating reagents prevented the T cell hybridomas from TCR-mediated ACD with minimal inhibition of IL-2 production. The elevated cytoplasmic cAMP did not block dexamethasone-induced apoptosis. This indicates that apoptosis is regulated by multiple pathways. Furthermore, the inhibitory effect of cAMP is specific for the TCR-mediated signaling pathway of ACD. Messenger RNA for bcl-2 was detected after treatment with forskolin.

Loss of heterozygosity at the bcl-2 gene locus and expression of bcl-2 in human gastric and colorectal carcinomas

The loss of heterozygosity (LOH) at the bcl-2 gene locus and the expression of the bcl-2 gene were examined in gastric and colorectal carcinoma cell lines and carcinoma tissues. LOH at the bcl-2 locus was detected in 24% (4/17) of gastric and 60% (6/10) of colonic carcinomas, all of which were well differentiated adenocarcinomas, whereas LOH was not seen in poorly differentiated ones. On the other hand, 24% (5/21) of poorly differentiated stomach cancers overexpressed bcl-2 gene, whereas no overexpression was detected in well differentiated stomach cancer. Three gastric and three colorectal carcinoma cell lines, all of which were derived from poorly differentiated adenocarcinomas, expressed considerable levels of bcl-2 mRNA and protein. These results suggest that LOH at the bcl-2 locus is frequently associated with well differentiated adenocarcinomas of the stomach and colon, and bcl-2 overexpression has implications for the development of poorly differentiated adenocarcinomas of the gastrointestinal tract.

[Secondary leukemia after etoposide treatment involved MLL gene rearrangement]

The 11q23 chromosomal abnormality is frequently observed in infantile leukemia and secondary leukemia, and the translocation associated gene in infantile leukemia is called mixed-lineage leukemia (MLL) gene. A 50-year-old man was admitted because of left axillary lymphadenopathy and IBL like T cell lymphoma was diagnosed by lymph node biopsy. The patient responded to the LSG-9 protocol with complete remission. After 10 months he was readmitted because of fever and was diagnosed acute myeloblastic leukemia by bone marrow aspiration. Chromosome analysis revealed 11q23 abnormality, suggesting that the leukemia was induced by etoposide treatment. Southern blot analysis demonstrated DNA rearrangement in the MLL gene at 11q23. It was suggested that the breakpoint region of the MLL gene in secondary leukemia is the same as that of infantile leukemia.

A reverse transcriptase-polymerase chain reaction detects heterogeneous chimeric mRNAs in leukemias with 11q23 abnormalities

The MLL gene involved in 11q23 translocations found in the majority of infantile leukemias and some secondary leukemias makes fusion transcripts with genes such as LTG4 (chromosome 4), LTG9 (chromosome 9), and LTG19 (chromosome 19) as a result of reciprocal translocation. We have examined 25 cases of leukemias with 11q23 abnormalities by Southern blot analysis and the reverse transcriptase-polymerase chain reaction (RT-PCR). Using various primer pairs, chimeric mRNAs could be amplified in 6 of 7 leukemias with t(4;11), 6 of 8 leukemias with t(9;11) including secondary leukemia, 8 of 9 leukemias with t(11;19), and 1 with a deletion at 11q23. The chimeric mRNAs were heterogeneous and differential usage of the MLL exons was found, irrespective of the partner chromosomes. Sensitivity studies showed that a single clone with chimeric mRNA in 10(4) to 10(5) cells could be detected. These findings show that the present RT-PCR settings provide a rapid, accurate, and sensitive tool for diagnosing leukemias with 11q23 translocations and for monitoring response to therapy in these patients.

Nuclear proteins binding to a novel target sequence within the recombination hotspot regions of Bcl-2 and the immunoglobulin DH gene family

The chromosomal breakpoints of follicular lymphomas carrying the t(14;18)(q32;q21) are known to be clustered within a 150-bp region in the major breakpoint region (mbr) of the Bcl-2 oncogene. We have demonstrated that nuclear proteins specifically bind to a novel target sequence within this 150-bp region and a region of Dxp genes, members of the immunoglobulin (Ig) diversity (DH) gene family. One protein, designated BCLF-1, appears to be specifically expressed in lymphoid lineage cells. Two other proteins, BCLF-2 and -3, bind only to the complementary single strand of the target sequence. The manner in which these proteins interact with the target sequence is similar to the interaction of the ReHF-1 and -2 proteins to the signal-like sequence at the chromosomal breakpoint junctions in patients with the t(8;14)(q24;q11) and t(1;14)(p32;q11) translocations. It was further suggested that the BCLF-1 is quite similar to or identical to the ReHF-1. It is therefore hypothesized that these conserved target sequences found in recombination hotspot regions may define novel sequence motifs recognized by two classes of DNA binding proteins. One class of DNA binding proteins is specifically expressed in lymphoid cells while the other class binds to the complementary single strand DNA. These binding activities may play a crucial role in chromosomal translocation in lymphoid neoplasms.

[Thirty seven cases of respiratory syncytial virus infection hospitalised and 7 severe cases with apneic attacks]

We studied 37 cases of respiratory syncytial virus infection hospitalized during the period January 1, 1989 and March 31, 1993. 37 patients were 0-4 years old on admission. Fever, positive CRP and elevation of BSG were frequent in patients aged 8 months-4 years old. Patient more than 8 months of age didn't need supplementation of oxygen. Of the 37 patients, we had one case who had hyponatremia and six cases who were admitted with severe apneic attacks required incubation. Of the six cases, one patient had delayed neurological deterioration after anoxia due to apneic attacks. He, followed up for 4 years, have serious residual deficits including spastic quadriplegia, delayed development and epilepsy. Variety of factors, including premature birth, young postnatal age and milk feeding appeared to be significant risk factors for sever infections of RSV. In RSV infection, apneic attacks can cause near-miss SIDS. So, we stress the importance of careful and rapid diagnosis for all infants less than 8 months of age.

Messenger RNA levels of five genes located at chromosome 11q13 in B-cell tumors with chromosome translocation t(11;14)(q13;q32)

To identify genes activated by chromosome translocation t(11;14)(q13;q32), mRNA levels of five genes (cyclin D1, EXP1, MB38, HST1, and INT2) at chromosome 11q13 were investigated. The cyclin D1 mRNA increased in BCL-1-rearranged B-cell tumor cell lines SP-49, NOP-2, FLAM-76, KMS-12-PE, and KMS-12-BM cells, while it was not detected in cell lines without the translocation, Raji, U266, and HEL cells. A significant amount of the MB38 mRNA was detected irrelevantly to the translocation in all of these cell lines. The mRNAs of EXP1, HST1, and INT2 were undetectable in these cells. The results suggested that the translocation activates cyclin D1 alone, while the mRNA levels of the other four genes are regulated independently of the translocation.

Local application of calcium antagonists inhibits intimal hyperplasia after arterial injury

The local effect of the calcium channel antagonist diltiazem and the protein kinase inhibitor 1-5-(isoquinoline sulfonyl)-5-homopiperazine HCL (HA1077) on neointimal formation after arterial injury were investigated by the use of a perivascular drug-delivery system. Bilateral carotid artery balloon injury was produced in 130 rats. In six groups of 10 rats each, diltiazem or HA1077 at three doses (low, 0.2 mg; medium, 1 mg; high, 5 mg) was mixed with the drug-delivery polymer poly(vinyl) alcohol and applied to the adventitial surface of the injured right carotid artery enclosed by a Silastic cuff; 10 control animals received polyvinyl alcohol only in the silastic cuff. In all animals, the contralateral injured artery without the cuff served as a control. At 10 and 20 days after the injury, the intimal cross-sectional area was determined from light microscopic sections for the injured segment of both carotid arteries. In six additional groups of 10 rats each, treated as above, levels of diltiazem and HA1077 in plasma were measured at periods from 1 hour to 5 days after perivascular application. At 10 days after endothelial injury, animals receiving high-dose diltiazem or HA 1077 (5 mg) demonstrated significant reductions in neointimal area compared with polyvinyl alcohol controls for both treated and contralateral untreated vessels. At 20 days after injury, neointimal hyperplasia was inhibited only on the treated side in both high-dose groups. Perivascular diltiazem and HA1077 at lower doses (1 or 0.2 mg) did not affect neointimal area at 10 or 20 days in either treated or untreated arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

An antibody for phosphorylated myosin light chain of smooth muscle: application to a biochemical study

An antibody with specificity for the 20 kDa myosin light chain of smooth muscle phosphorylated by myosin light chain kinase was developed. The antibody was raised against the phosphorylated synthetic peptide, Lys-Lys-Arg-Pro-Gln-Arg-Ala-Thr-phospho-Ser-Asn-Val-Phe-Cys (residues 11-22 of the myosin light chain). This antibody only recognized the monophosphorylated myosin light chain at serine 19, i.e., with no detectable recognition of nonphosphorylated or diphosphorylated serine 19 or threonine 18. The specificity was tested by EIA assaying of myosin light chain kinase activity using a 96-well plate coated with the light chain. This EIA system was as sensitive as the radioisotopic method, and the newly developed non-radioisotopic method.

Rearrangement of bcl-2 genes in malignant lymphomas in Chinese patients

BACKGROUND

Only a small percentage of Asian patients with non-Hodgkin lymphoma may have follicular type disease. According to molecular analysis done recently, the incidence of rearrangement of bcl-2 gene in patients with follicular lymphoma was lower in Japan than in the United States, suggesting possible geographic or racial differences between Asian and Western populations. The current study was undertaken to obtain data from Taiwan to compare with data from Japan, Hong Kong, and Western countries.

METHODS

Using probes of genomic 5' bcl-2, major breakpoint region (mbr) and minor breakpoint cluster region (mcr) for the breakpoint cluster region of the bcl-2 gene, genomic DNA samples from 55 patients with B-cell lymphoma (17 with follicular type and 38 with diffuse type) were analyzed by Southern blot analysis.

RESULTS

Eleven patients had bcl-2 gene rearrangement, including 9 of 17 (52.9%) patients with follicular lymphoma and 2 of 38 (5.3%) patients with diffuse B-cell lymphoma. Nine patients had the breakpoint located within the mbr, one at both the mbr and the 5' bcl-2 regions, and the other had bcl-2 translocation with involvement of the mcr. DNA fragment of bcl-2 was found to comigrate with JH genes in all patients with follicular lymphoma and diffuse lymphoma who had bcl-2 rearrangement at mbr. The remaining patient who had bcl-2 translocation at mcr had no comigration with JH, Jk, or C lambda genes.

CONCLUSIONS

Despite the low incidence of follicular lymphoma in Chinese patients, the incidence of bcl-2 gene involvement was higher in patients from Taiwan than in those from Japan and Hong Kong, but similar to the incidence of those from Western countries.

Long-range mapping of the 11q23 region involved in chromosome aberrations in human tumors by pulsed-field gel electrophoresis with a yeast artificial chromosome

We have previously demonstrated that the RCK gene involved in t(11;14)(q23;q32) and the more centromeric MLL/ALL1 gene involved in t(4;11)(q21;q23) and t(11;19)(q23;p13) are localized on different adjacent NotI fragments by using pulsed-field gel electrophoresis (PFGE) analysis with the yeast artificial chromosome (YAC) clone yB22B2. The PFGE analysis using the YACs of YTY17 containing the prophobilinogen deaminase (PBGD), CBL2 and THY1 genes and yB22B2 allowed the following ordering of genes and breakpoints from CD3 to THY1 on 11q23: cent-CD3-ALL/MLL1-RCK-PBGD-CBL2-THY1, and the establishment of a long-range restriction map covering these genes. In addition, we showed that the FLI1 region involved in the t(11;22)(q24;q12) in Ewing's sarcoma was more telomeric region that the THY1 gene by analyzing somatic cell hybrids carrying the 11q- and/or 14q+ chromosome of the t(11;14)(q23;q32) translocation, and by PFGE analysis of the YAC clone YTY17.

MLLT3 gene on 9p22 involved in t(9;11) leukemia encodes a serine/proline rich protein homologous to MLLT1 on 19p13

Recently, the MLL gene at 11q23 was found to be involved in a subset of leukemias with an 11q23 abnormality. In the present study, we isolated chimeric cDNAs between the MLL and a gene designated MLLT3 at 9p22 from a cDNA library of an IMS-M1 cell line with a t(9;11)(p22;q23) translocation, a representative karyotypic abnormality seen in acute monocytic leukemia. We also isolated a normal MLLT3 cDNA and found an open reading frame encoding at least 318 amino acids with high serine/proline content (24.8%). The chimeric mRNAs were demonstrated to be fused to MLL in frame, as found in t(11;19) and t(4;11) leukemias. The predicted MLLT3 protein demonstrated a significant homology to that of the MLLT1 gene at 19p13 involved in t(11;19) leukemia. The highest homology, up to 74.1%, was found in 86 amino acids of the C-terminus, suggesting that this region is of particular importance for leukemogenesis in t(9;11) leukemia. Northern blot analysis with the MLLT3 cDNA probe against normal tissues revealed multiple transcripts in lymphoid organs. A survey of hematopoietic cell lines demonstrated relatively stronger signals in cells belonging to megakaryocytic and erythroid lineages. As previously found in t(11;19) leukemia, heterogeneous MLL-MLLT3 chimeric mRNAs could be detected by the reverse transcriptase-polymerase chain reaction (RT-PCR) in t(9;11) leukemia samples.

Two distinct portions of LTG19/ENL at 19p13 are involved in t(11;19) leukemia

We previously isolated cDNA clones, MLL-a and MLL-b, derived from the 11q23 breakpoint region and detected gene rearrangements with MLL-b cDNA in infantile leukemia cell lines with 11q23 abnormalities. We also showed chimeric mRNAs between MLL and genes on partner chromosomes such as 4q21 and 19p13. In the present study, we isolated overlapping MLL cDNA clones of 11 kb and demonstrated that MLL-a and MLL-b were derived from the same gene, MLL/ALL-1/HRX. Northern analysis with an MLL cDNA probe detected different signals in t(11;19) cell lines, one being sized 10 kb in two cell lines, KOCL-33 and KOCL-44, and the other being 9.2 kb in the cell line, KOPN-1. To elucidate the molecular basis for the heterogeneity, we isolated cDNA clones of a translocation-associated gene on chromosome 19, LTG19, as well as chimeric cDNAs from KOPN-1. Northern analysis with LTG19 cDNA demonstrated the identical gene, encoding serine/proline rich 559 amino acid polypeptide, to be involved in all three cell lines. Sequence comparison revealed that the LTG19 portion of the predicted chimeric protein of KOPN-1 was fused in frame and contained the C-terminal 189 amino acids. This was shorter by 366 amino acids than those of KOCL-33 and KOCL-44, also fused in frame. Reverse transcriptase-PCR analysis demonstrated complex chimeric mRNAs in cell lines and leukemia samples. Although a chimeric mRNA of KOPN-1 type was rare, its presence suggested that the shared C-terminal portion of 189 amino acids of LTG19 contains important signal(s) for malignant transformation.

Overexpression of PRAD1 in a mantle zone lymphoma patient with a t(11;22)(q13;q11) translocation

The PRAD1 gene identified from the chromosome band 11q13 region was previously demonstrated to be overexpressed in cell lines with t(11;14)(q13;q32) translocation and was suggested to be a candidate BCL-1 gene. We report here one case of mantle zone lymphoma with a t(11;22)(q13;q11), a variant translocation at the BCL-1 locus, having the PRAD1 overexpression. By analogy with the c-myc gene in Burkitt's lymphoma and the BCL-2 gene in follicular lymphoma, this case supports strongly the idea that the PRAD1 is the candidate BCL-1 gene.

Molecular cloning of 19p13 breakpoint region in infantile leukemia with t(11;19)(q23;p13) translocation

We studied the breakpoint regions involved in t(11;19)(q23;p13) translocation associated with infantile leukemias. Southern blot analysis with the partial cDNA clone for the MLL gene at 11q23 which we had isolated previously detected gene rearrangements in all three cell lines and three leukemia samples from the patients with t(11;19) translocation, indicating that these breakpoints were clustered within the 8.5 kb BamHI germline fragment detected by the probe. To study the breakpoint region, a genomic library of one of the cell lines, KOCL-33, was made. We have isolated the der(19) allele containing the breakpoint as well as the germline alleles at 19p13 and 11q23. Using the genomic probes on chromosome 19 near the breakpoint, Southern blot analysis was performed. The breakpoints at 19p13 of the two other cell lines and the three leukemia samples were not located within 36 kilobases of the KOCL-33 breakpoint, although pulsed-field gel electrophoresis showed that the breakpoints of all three cell lines were on the same NruI fragment of 230 kilobases. These results showed that the breakpoints at 19p13 were not clustered like those at 11q23 in t(11;19) translocation.

Novel interleukin-2 dependent T-cell line derived from adult T-cell leukemia not associated with human T-cell leukemia virus type I

A novel interleukin-2 (IL-2)-dependent T-cell line, WHN2, was established from a patient with adult T-cell leukemia (ATL) not associated with human T-cell leukemia virus type I (HTLV-I). Neither the original leukemic cells nor the WHN2 cells showed proviral integration in their cellular DNAs by Southern blot analysis. The surface phenotype showed that both the original leukemic cells and the WHN2 cells had a common phenotype of ATL, i.e., positive for CD2, CD4, human leukocyte antigen DR (HLA-DR) and CD25, but negative for CD8, a characteristic of helper/inducer T-cells. Most of the chromosomal abnormalities of the original leukemic cells were maintained in the WHN2 cell line. Furthermore, Southern blot analysis of the T-cell receptor beta-chain gene rearrangement revealed that the original leukemic cells and WHN2 cell line had identical patterns, suggesting that the WHN2 cell line was truly derived from the original leukemic cells. Dose-dependent growth on IL-2 was demonstrated, and at the maximal stimulation, the number of cells doubled within three days. This IL-2-dependent growth was inhibited by the simultaneous existence of anti-IL-2 receptor alpha and beta chain antibodies. These results indicate that the character of the WHN2 cell line is similar to that of the cell lines derived from ATL associated with HTLV-I. Thus, the HTLV-I-negative ATL cell line, WHN2, should be useful in the comparative study of the pathogenesis of ATL associated with or without HTLV-I.

[An outbreak of Pseudomonas sepsis associated with nosocomial infection in a pediatric ward]

A five-year old girl, diagnosed with fever of unknown origin (FUO), was transferred to our hospital due to a deterioration in her general condition. Pseudomonas cepacia (P. cepacia) was detected in her blood culture and she soon recovered after imipenem cilastatin (IPM/CS) administration. When the former hospital was informed of the results of her blood cultures, we learned that five other cases of FUO had occurred there within the previous two weeks in noncompromised children. Except for one case, Pseudomonas species was detected in their blood cultures. P. cepacia was found in one case, Pseudomonas aeruginosa (P. aeruginosa) was detected in two other cases, and both P. cepacia and P. aeruginosa were demonstrated in the other patient. Although the origin of the bacteria is unknown, it may have spread to the children through a contaminated liquid reservoir or medical devices.

Gene rearrangement and truncated mRNA in cell lines with 11q23 translocation

We have previously demonstrated that the breakpoints of t(11;19)(q23;p13) leukemias are within 360 kb of the CD3 gene. One of the phage clones, 6n, which was isolated from the yeast artificial chromosome clone yB22B2 containing CD3, was found to be within 60 kb of t(11;19) breakpoints. In this study, gene walking was conducted and two phage clones (lambda Hp8-3 and lambda Hp23-13) were isolated from a human placenta genomic library. Southern blot analysis with a genomic probe from lambda Hp8-3 detected gene rearrangements in t(4;11) and t(11;19) cell lines with BamHI digestion. Subsequently, using reiterated sequence-free probes from both ends of 6n that detected transcriptional units in various hematopoietic cells, we isolated cDNA clones. These cDNA clones were classified into two groups (designated MLL-a and MLL-b), which do not hybridize to each other. Northern blot analysis with MLL-a cDNA detected 15-, 14- and 12-kb mRNAs, while MLL-b detected the additional 9.7- and 5-kb mRNAs in peripheral blood lymphocytes. MLL-b cDNA detected a truncated form of 12.5-kb mRNA in t(4;11) cell lines and a truncated form of 10-kb or 9.2-kb mRNA in t(11;19) cell lines. MLL-a did not demonstrate a truncated form of mRNA, but the stronger 14-kb signal was noted in t(4;11) cells, while this signal was very weak in t(11;19) cells. By Southern blot analysis, MLL-b cDNA detected gene rearrangement in cell lines with t(4;11) and t(11;19), whereas MLL-a did not. Furthermore, chimeric cDNA clones were isolated from cDNA libraries of t(4;11) and t(11;19) cell lines with a MLL-b cDNA probe. These results indicate that the MLL-b cDNA is derived from the common target gene involved in 11q23 translocation with 4q21 or 19p13.

Intimal hyperplasia enhances myosin phosphorylation in rabbit carotid artery

We examined physiological events in the hyperplastic artery, using a method based on the mechanical responsiveness and myosin light-chain phosphorylation in response to various stimulants. Six weeks after endothelial denudation by ballooning of the right carotid artery, strips of this artery with moderate intimal hyperplasia (intimal area was 30-50% of medial area in 20 of 28 rabbits) were used for experiments. Strips from the left carotid served as the normal control. When the hyperplastic artery was stimulated with 30 microM PGF2 alpha, the maximal tension (232.4 +/- 49.1 mg/mg dry wt, mean +/- SD) was significantly higher (P < 0.05) than that of the control (129.5 +/- 16.4 mg/mg). The maximal extent of myosin light-chain monophosphorylation (45.4 +/- 8.9%) and diphosphorylation (10.9 +/- 5.2%) in the hyperplastic artery was significantly higher (P < 0.05) than that in the control artery (33.0 +/- 4.8 and 4.0 +/- 4.8%, respectively). The monophosphorylation of the myosin light chain in the hyperplastic artery was sustained for up to 20 min, while that in the control artery decreased to the basal level within 20 min. Similar observations were obtained by stimulation with 60 mM K+ or 30 microM norepinephrine. Dose-response curves of the development of tension in the hyperplastic artery to various agonists (K+, PGF2 alpha, norepinephrine) shifted upward the curves for the control artery. These results suggest that qualitative changes in the characteristics of smooth muscle cells may occur in the intimal hyperplastic portion, including a hyperreactive contraction associated with enhanced and sustained phosphorylation of the myosin light chain.

Isolation and characterization of mouse CD7 cDNA

The human CD7 antigen is a glycoprotein, M(r) 40,000, expressed on the surface of peripheral blood T-lymphocytes and thymocytes, and is the earliest surface antigen to appear on T-cell lineage cells. In this study, putative mouse CD7 cDNA was identified based on its similarities with human CD7. Five independent clones originating from the same mRNA species were isolated (designated as mCD7) by screening a mouse thymocyte cDNA library with human CD7 cDNA, J61, under moderate stringency. The longest insert of a 995 base pair had an open reading frame of 210 amino acids. Northern blot analysis using the mouse CD7 cDNA probe demonstrated a single 1.2 kilobase mRNA in the thymus, spleen, bone marrow, and small intestine. The protein deduced from mCD7 cDNA consisted of the leader, extracellular, transmembrane, and cytoplasmic domains of 24, 126, 21, and 39 amino acids, respectively, based on the hydrophobicity plot and the structure of human CD7. The extracellular domain contained three potential N-glycosilation sites, while the cytoplasmic domain contained one potential protein kinase C phosphorylation site. The amino acid sequence had 45.5% similarity with human CD7, while the similarities for the individual domains ranged from 49.2% to 63.2%. The six highly conserved regions, which may possibly be involved with still unknown CD7-mediated functions, were located in the extracellular and cytoplasmic domains.

Expression of the c-kit protein in human solid tumors and in corresponding fetal and adult normal tissues

The proto-oncogene c-kit encodes a transmembrane tyrosine kinase receptor that is thought to play an important role in hematopoiesis, spermatogenesis, and melanogenesis. We previously showed that the c-kit messenger RNA is preferentially expressed in small cell lung cancer and that its ligand, stem cell factor, is expressed in a broad spectrum of human cancers. Using anti-c-kit antisera raised against synthetic peptides, in situ localization of the c-kit protein in various human solid tumors as well as in corresponding fetal and adult normal tissues was studied by the ABC method. The results suggest that the c-kit gene products may be involved in the pathogenesis of a very restricted subset of human solid tumors such as small cell lung cancer. Interestingly, nuclear protein immunologically related to c-kit was found in both normal and neoplastic medullary cells of the adrenal gland.

Treatment of myasthenia gravis: a comparison of the natural course and current therapies

Ninety-five patients with generalized myasthenia gravis were followed for 10 years to evaluate the long term effects of prednisolone, thymectomy, or both, and they were compared with a group only with anticholinesterase treatment. Only 15.0% of the patients with anticholinesterase alone had showed improvement 10 years after the onset, but more than 60% of those treated with prednisolone, thymectomy, or both showed improvement. Especially thymectomy induced complete remissions at 10 years after surgery in more than 20% of the patients. There was no difference between the histology of the thymi and clinical severity, or anti-acetylcholine receptor (AChR) antibody titer. In patients who showed improvement classified "good" of higher 10 years after thymectomy with or without prednisolone, anti-AChR antibody titers swiftly decreased to 37.8% of the value before surgery, and remained low thereafter. This result suggests that the marked decrease in anti-AChR antibody titers within 1 month after thymectomy is a favorable prognostic sign in myasthenia gravis patients who have undergone thymectomy.

Isolation of a novel cDNA clone showing marked similarity to ME491/CD63 superfamily

A novel cDNA clone, A15, was isolated by the differential screening of a cDNA library of an immature T cell line, HPB-ALL using radioactive cDNA probes from the mRNA of either HPB-ALL or peripheral blood lymphocytes. It hybridized to a single mRNA species of about 2.0 kilobases which is expressed in HPB-ALL cell line, but not in the PBL or a promyelocytic leukemia cell line, HL-60. The A15 gene codes for a protein of 244 amino acids which contains four potential transmembrane domains and four possible N-linked glycosylation sites. A computer-aided comparison showed a marked similarity to several other membrane proteins: CD9, CD37, CD53, TAPA-1, Sm23, CO-029, and ME491/CD63.

Phenotypic and genotypic characterization of 14 leukemia and lymphoma cell lines with 11q23 translocations

11q23 translocation is the most popular chromosomal abnormality in infant leukemia. In adults, it is often encountered in non-Hodgkin's lymphoma (NHL). In this study, we analyzed the phenotypic and genotypic characteristics of 9 acute leukemic cell lines with 11q23 translocations and one with deletion of the 11q23 locus, nine of which were established by researchers in this group, together with 4 NHL cell lines with 11q23 translocations. All lines were considered to belong to the B-cell lineage at different stages. All 10 leukemic lines showed clonal rearrangement of the immunoglobulin heavy chain (IgH) gene: two corresponded to the B-precursor stage (CD19+, cytoplasmic mu-), while the other 8 corresponded to the pre-B stage (cytoplasmic mu+). All 4 NHL lines showed rearrangements of both the IgH and Ig kappa genes with three expressing surface Ig; specifically, mature B-cell phenotype. As for myelocytic-monocytic markers, at least one out of 4 antigens examined were positive in 8 of the 10 leukemic cell lines, while only one of the 4 NHL lines was reactive. There were essentially no clear phenotypic or genotypic differences between t(4;11) and t(11;19) cell lines, supporting the view that both diseases have similar clinicopathological characteristics. These cell lines are also valuable for cloning genes at the chromosomal breakpoints.