Downregulation of voltage-gated K(+) channels in rat heart with right ventricular hypertrophy

The effects of myocardial hypertrophy on mRNA expression levels of voltage-gated K(+) channels were investigated using monocrotaline (MCT)-induced pulmonary hypertensive rats. The ratio of right ventricle weight to left ventricle plus septum weight on day 28 was increased significantly compared with control rats [control vs. MCT: 0.27 +/- 0.01 vs. 0.58 +/- 0.03 ms (n = 8-13); P < 0.05]. Electrocardiograms showed that QRS duration [control vs. MCT: 26.4 +/- 2.6 ms vs. 31.5 +/- 5.8 ms (n = 6); P < 0.05], Q-T interval [control vs. MCT: 100.8 +/- 8.9 ms vs. 110.0 +/- 4.2 ms (n = 6); P < 0.05] and corrected Q-T interval [Q-T(c); control vs. MCT: 8.4 +/- 0. 7 ms vs. 10.2 +/- 0.4 ms (n = 6); P < 0.05] were prolonged significantly on day 28. mRNA levels of Kv1.2, 1.5, 2.1, 4.2, and 4. 3 for day 28 assessed by ribonuclease protection assays were decreased significantly from control by 60 +/- 10, 76 +/- 3, 58 +/- 5, 81 +/- 5, and 45 +/- 12%, respectively (n = 3; P < 0.005), and Kv1.4 mRNA level for day 28 was unaffected [Kv1.4, control vs. MCT: 1.0 +/- 0.28 vs. 0.88 +/- 0.44 (arbitrary units) (n = 3); not significant (NS)]. On the other hand, there was no significant difference between control and MCT rats in mRNA levels of these Kv channels for day 14 [Kv1.2 (control vs. MCT): 1.0 +/- 0.25 vs. 0.87 +/- 0.18 (n = 3), NS; Kv1.4: 1.0 +/- 0.22 vs. 1.27 +/- 0.37 (n = 3), NS; Kv1.5: 1.0 +/- 0.16 vs. 0.91 +/- 0.28 (n = 3), NS; Kv2.1: 1.0 +/- 0.26 vs. 0.99 +/- 0.25 (n = 3), NS; Kv4.2: 1.0 +/- 0.15 vs. 1.22 +/- 0.28 (n = 3), NS; Kv4.3: 1.0 +/- 0.20 vs. 1.21 +/- 0.28 (n = 3), NS]. These findings suggest that altered ventricular repolarization at the advanced stage of hypertrophy may be the result of an inhibition of gene expression of multiple types of voltage-gated K(+) channels.

NG2+ glial cells: a novel glial cell population in the adult brain

We describe a major glial cell population in the central nervous system (CNS) that can be identified by the expression of 2 cell surface molecules, the NG2 proteoglycan and the alpha receptor for platelet-derived growth factor (PDGF alphaR). In vitro and in the developing brain in vivo, NG2 and PDGF alphaR are expressed on oligodendrocyte progenitor cells but are down-regulated as the progenitor cells differentiate into mature oligodendrocytes. In the mature CNS, numerous NG2+/PDGF alphaR+ cells with extensive arborization of their cell processes are found ubiquitously long after oligodendrocytes are generated. NG2+ cells in the mature CNS do not express antigens specific to mature oligodendrocytes, astrocytes, microglia, or neurons, suggesting that they are a novel population of glial cells. Recently NG2+ cells in the adult CNS have been shown to undergo proliferation and morphological changes in response to a variety of stimuli, such as demyelination and inflammation, suggesting that they are dynamic cells capable of responding to changes in the environment. Furthermore, high levels of NG2+ and PDGF alphaR are expressed on oligodendroglioma cells, raising the possibility that the NG2+/PDGF alphaR+ cells in the mature CNS contribute to glial neoplasm.

Induction of L-phenylalanine ammonia-lyase and suppression of veratryl alcohol biosynthesis by exogenously added L-phenylalanine in a white-rot fungus phanerochaete chrysosporium

The effects of exogenously added L-phenylalanine (L-Phe) on the activities of L-phenylalanine ammonia-lyase (PAL) and 3, 4-dimethoxybenzyl alcohol (veratryl alcohol, VA) biosynthesis in ligninolytic cultures of Phanerochaete chrysosporium were investigated. Increasing PAL activity was detected in low nitrogen (LN) culture but not in high nitrogen (HN) culture. The addition of L-Phe into the LN culture caused a 25-fold increase in enzyme activity, which clearly shows that L-Phe, a substrate of the enzyme, served as an inducer of PAL. The increase in activity of PAL triggered by nitrogen starvation was correlated with biosynthesis of VA. However, PAL induced by the added L-Phe did not promote VA biosynthesis but suppressed the biosynthesis probably due to NH(4)(+) released from L-Phe.

Cytoskeletal reorganization induced by engagement of the NG2 proteoglycan leads to cell spreading and migration

Cells expressing the NG2 proteoglycan can attach, spread, and migrate on surfaces coated with NG2 mAbs, demonstrating that engagement of NG2 can trigger the cytoskeletal rearrangements necessary for changes in cell morphology and motility. Engagement of different epitopes of the proteoglycan results in distinct forms of actin reorganization. On mAb D120, the cells contain radial actin spikes characteristic of filopodial extension, whereas on mAb N143, the cells contain cortical actin bundles characteristic of lamellipodia. Cells that express NG2 variants lacking the transmembrane and cytoplasmic domains are unable to spread or migrate on NG2 mAb-coated surfaces, indicating that these portions of the molecule are essential for NG2-mediated signal transduction. Cells expressing an NG2 variant lacking the C-terminal half of the cytoplasmic domain can still spread normally on mAbs D120 and N143, suggesting that the membrane-proximal cytoplasmic segment is responsible for this process. In contrast, this variant migrates poorly on mAb D120 and exhibits abnormal arrays of radial actin filaments decorated with fascin during spreading on this mAb. The C-terminal portion of the NG2 cytoplasmic domain, therefore, may be involved in regulating molecular events that are crucial for cell motility.

Mouse glutaredoxin - cDNA cloning, high level expression in E. coli and its possible implication in redox regulation of the DNA binding activity in transcription factor PEBP2

We have isolated a cDNA encoding glutaredoxin (GRX) from a mouse splenic cDNA library. This cDNA encoded a protein of 107 amino acids with a calculated molecular weight of 11.9 kDa. The deduced amino acid sequence of glutaredoxin in mouse was highly homologous with that in other mammals (81-89%), containing a putative active sequence of -Cys-Pro-Try-Cys-. Recombinant mouse glutaredoxin expressed in E. coli showed glutathione-disulfide oxidoreductase activity with beta-hydroxyethyl disulfide as its substrate, whereas mutant glutaredoxin (Cys 22, Cys 25 to Ser) showed no activity. In electrophoretic mobility shift assay, we proved that wild type GRX, not mutant one, recovered the DNA-binding activity of a transcription factor, PEBP2, oxidized by diamide. This showed that GRX may be involved in the redox regulation of the DNA-binding activity of PEBP2 as is the case with thioredoxin.

Effects of bisphosphonate on experimental jaw metastasis model in nude mice

The mechanism of osteolysis associated with metastatic cancer of the jaws is essentially osteoclast-mediated. Therefore, it is likely that potent osteoclastic bone resorption inhibitors such as bisphosphonates would be efficacious for the treatment of jaw metastasis. We examined the effects of a third generation bisphosphonate, YM175, in a nude mice jaw metastasis model with intracardiac injection of a human breast cancer cell line, MDA-MB-231. The metastatic lesions in untreated mice were radiographically observed at the body and angle of the mandible. Histology of the mandible of untreated mice revealed that most of the bone marrow cavities had been occupied by the metastatic tumor with active osteoclasts along the trabecular bone. The experimental group showed that YM175 markedly reduced the size of tumor and the number of osteoclasts. These results suggest that YM175 may suppress metastasis formation and tumor growth in jaw through inhibition of osteoclastic bone resorption.

Expression of oligodendrocyte progenitor cell antigens by gliomas: implications for the histogenesis of brain tumors

The early events in neoplastic transformation can be understood only by comparison of the neoplastic cell with its nontransformed counterpart. The most common central nervous system gliomas traditionally are thought to arise from mature astrocytes and oligodendrocytes. We examined the possibility that gliomas arise from a population of glia that has properties of oligodendrocyte progenitors. These glial cells express the NG2 chondroitin sulfate proteoglycan and the alpha receptor of platelet-derived growth factor in vivo. We identified NG2 and the alpha receptor of platelet-derived growth factor expression in tissue from seven of seven oligodendrogliomas, three of three pilocytic astrocytomas, and one of five glioblastoma multiforme. These data provide evidence that glial tumors arise from glial progenitor cells. Molecules expressed by these progenitor cells should be considered as targets for novel therapeutics.

Th2 T cells expressing transgene PDGF-A serve as vectors for gene therapy in autoimmune demyelinating disease

We hypothesized that T cells can be genetically modified to express growth factor transgene products capable of inducing oligodendrocyte progenitor proliferation. Autoreactive T cells isolated from SWXJ mice immunized with the p139-151 determinant of myelin proteolipid protein (PLP) were transfected with an antigen-inducible transgene for platelet-derived growth factor-A (PDGF), a growth factor important in regulating the development of oligodendrocytes. Isolated antigen-specific T cell clones expressed the PDGF transgene when stimulated with PLP 139-151 peptide and produced biologically active PDGF capable of inducing proliferation of oligodendrocyte progenitor cells. Furthermore, upon adoptive transfer, the PDGF transfected T cells migrated to the CNS and ameliorated ongoing disease. Our data indicate that autoreactive memory Th2 cells can be genetically modified so that upon engagement with self antigen they produce regenerative growth factors capable of mediating tissue repair during autoimmune disease.

Identification of thioredoxin-binding protein-2/vitamin D(3) up-regulated protein 1 as a negative regulator of thioredoxin function and expression

Recent works have shown the importance of reduction/oxidation (redox) regulation in various biological phenomena. Thioredoxin (TRX) is one of the major components of the thiol reducing system and plays multiple roles in cellular processes such as proliferation, apoptosis, and gene expression. To investigate the molecular mechanism of TRX action, we used a yeast two-hybrid system to identify TRX-binding proteins. One of the candidates, designated as thioredoxin-binding protein-2 (TBP-2), was identical to vitamin D(3) up-regulated protein 1 (VDUP1). The association of TRX with TBP-2/VDUP1 was observed in vitro and in vivo. TBP-2/VDUP1 bound to reduced TRX but not to oxidized TRX nor to mutant TRX, in which two redox active cysteine residues are substituted by serine. Thus, the catalytic center of TRX seems to be important for the interaction. Insulin reducing activity of TRX was inhibited by the addition of recombinant TBP-2/VDUP1 protein in vitro. In COS-7 and HEK293 cells transiently transfected with TBP-2/VDUP1 expression vector, decrease of insulin reducing activity of TRX and diminishment of TRX expression was observed. These results suggested that TBP-2/VDUP1 serves as a negative regulator of the biological function and expression of TRX. Treatment of HL-60 cells with 1alpha, 25-dihydroxyvitamin D(3) caused an increase of TBP-2/VDUP1 expression and down-regulation of the expression and the reducing activity of TRX. Therefore, the TRX-TBP-2/VDUP1 interaction may be an important redox regulatory mechanism in cellular processes, including differentiation of myeloid and macrophage lineages.

Characteristics of blood pressure measured at home in the morning and in the evening: the Ohasama study

OBJECTIVE

To determine the qualitative and quantitative differences of blood pressure measured at home (home measurement) in the morning versus the evening.

METHODS

Of 3744 participants, aged 20 years or older in the Ohasama population, more than 14 home measurements in the morning and in the evening, respectively, were obtained in each of 1207 individuals (881 untreated, 56.1 +/- 11.4 years and 326 treated, 66.0 +/- 9.2 years). A casual/screening measurement was also obtained in these individuals.

RESULTS

The home measurements in the morning were significantly higher than those in the evening. The bivariate linear regression analysis demonstrated that the difference between diastolic home measurement in the morning and that in the evening increased with an increase in diastolic home measurements. The multiple step-wise linear regression analysis, however, demonstrated that male sex, the use of antihypertensive medication, and SD of home measurements in individuals (blood pressure variability), but not level of home measurements, were positively associated with the difference between home measurement in the morning and that in the evening. The SD of home measurement in the evening in individuals was significantly larger than that in the morning, and the SD in treated individuals was significantly larger than that in untreated individuals. The correlations between casual and home measurements were moderate in untreated individuals (r = 0.509-0.567) but poor in treated subjects (r= 0.223-0.384). The correlations between home systolic measurements in the morning and in the evening were very close in both treated and untreated subjects (r = 0.814-0.902). The correlations between the SD of home measurements in the morning and in the evening were moderate in both treated and untreated individuals (r = 0.585-0.657).

CONCLUSIONS

Qualitative and quantitative differences in home blood pressure measurement, due to the differential time of measurement, should be taken into consideration in clinical use of home blood pressure measurements.

[Influence of tooth contacts during mandibular retrusion on terminal jaw relations and EMG activity during habitual opening and closing movements]

The purpose of this study was to clarify the influence of tooth contacts during mandibular retrusion on terminal jaw relations (TJR) and the surface EMG activity during habitual opening and closing movements. The age of five healthy subjects were 25 to 28 years. The maxillary stabilization splints with steep retrusive contacts (S-SP) and with flat retrusive contacts (F-SP) were prepared for each subject who was instructed to wear S-SP for one week and then to wear F-SP for one week after an interval of two weeks without S-SP. The EMG activity of the masseter and temporal muscles and the TJR during habitual opening and closing movements using a device for recording jaw movements in 6 degrees of freedom were simultaneously measured by an intraoral central bearing device. The results were as follows: 1. The TJR recorded after wearing F-SP shifted more posteriorly than that of wearing S-SP. 2. The posterior temporal muscle activity after wearing F-SP, compared with that of wearing S-SP, resulted in a significant increase. In conclusion, the elimination of the retrusive guidance caused the predominance of posterior temporal muscle activity, and posterior displacement of the mandible.

Localization of glutaredoxin (thioltransferase) in the rat brain and possible functional implications during focal ischemia

We investigated the distribution of glutaredoxin (GRX, thioltransferase) in the rat brain using the in situ hybridization and immunohistochemical methods. GRX mRNA and GRX were expressed widely in the rat brain. The endothelial cell, tanycyte and ependymal cell expressed GRX mRNA and GRX protein. Neurons in various regions also showed GRX mRNA and GRX. Among them, pyramidal neurons in hippocampal CA3 region expressed a higher level of GRX mRNA. In addition, GRX mRNA signals were reduced after middle cerebral artery occlusion. Immunohistochemical analysis for GRX also revealed that GRX was reduced after ischemia. Northern blot analysis also showed that GRX mRNA from ischemic hemispheres decreased after ischemia. This reduction was parallel with the neuronal damage. This observation indicated that the maintenance of GRX and the redox regulating system was important for neuronal survival against oxidative stress.

Demonstration of the interaction of thioredoxin with p40phox, a phagocyte oxidase component, using a yeast two-hybrid system

Thioredoxin (TRX) has disulfide reducing activity and is reported to be involved in various cellular functions including the promotion of cell growth and apoptosis. To help understand the molecular mechanism through which TRX is involved in immunological systems, we screened a cDNA library derived from a B-cell population of Epstein-Barr virus-transformed human peripheral blood lymhocyte for TRX binding proteins by use of a yeast two-hybrid system. Among plasmids from positive clones, a plasmid contained an insert which has homology with human p40phox, a cytosolic component of phagocyte oxidase. This insert sequence extended from the base + 181 to the stop codon of p40phox. The entire coding region of p40phox was shown to interact with TRX both in assays of histidine prototrophy and beta-galactosidase activity; in contrast, no interaction was observed with substituted mutant TRX (C32S/C35S), which lacks reducing activity. These results showed that p40phox interacts with TRX and indicated the possibility of TRX-dependent regulation of phagocyte oxidase activity.

Overexpression of thioredoxin in transgenic mice attenuates focal ischemic brain damage

Thioredoxin (TRX) plays important biological roles both in intra- and extracellular compartments, including in regulation of various intracellular molecules via thiol redox control. We produced TRX overexpressing mice and confirmed that there were no anatomical and physiological differences between wild-type (WT) mice and TRX transgenic (Tg) mice. In the present study we subjected mice to focal brain ischemia to shed light on the role of TRX in brain ischemic injury. At 24 hr after middle cerebral artery occlusion, infarct areas and volume were significantly smaller in Tg mice than in WT mice. Moreover neurological deficit was ameliorated in Tg mice compared with WT mice. Protein carbonyl content, a marker of cellular protein oxidation, in Tg mice showed less increase than did that of WT mice after the ischemic insult. Furthermore, c-fos expression in Tg mice was stronger than in WT mice 1 hr after ischemia. Our results suggest that transgene expression of TRX decreased ischemic neuronal injury and that TRX and the redox state modified by TRX play a crucial role in brain damage during stroke.

PDGF (alpha)-receptor is unresponsive to PDGF-AA in aortic smooth muscle cells from the NG2 knockout mouse

A line of null mice has been produced which fails to express the transmembrane chondroitin sulfate proteoglycan NG2. Homozygous NG2 null mice do not exhibit gross phenotypic differences from wild-type mice, suggesting that detailed analyses are required to detect subtle alterations caused by the absence of NG2. Accordingly, dissociated cultures of aortic smooth muscle cells from null mice were compared to parallel cultures from wild-type mice for their ability to proliferate and migrate in response to specific growth factors. Both null and wild-type smooth muscle cells exhibited identical abilities to proliferate and migrate in response to PDGF-BB. In contrast, only the wild-type cells responded to PDGF-AA in both types of assays. NG2 null cells failed to proliferate or migrate in response to PDGF-AA, implying a defect in the signaling cascade normally initiated by activation of the PDGF (alpha)-receptor. In agreement with this idea, activation of the extracellular signal-regulated kinase (ERK) in response to PDGF-AA treatment occured only in wild-type cells. Failure to observe autophosphorylation of the PDGF (alpha)-receptor in PDGF-AA-treated null cells indicates that the absence of NG2 causes a defect in signal transduction at the level of (alpha)-receptor activation.

Effects of halothane on renal hemodynamics and interstitial nitric oxide in rabbits

The effects of halothane on renal hemodynamics and the nitric oxide (NO)-guanylate cyclase signaling pathway were examined in anesthetized rabbits using a renal microdialysis method. Halothane (0.5 and 2 vol%) caused dose-dependent decreases in blood pressure, renal blood flow and the renal interstitial concentrations of guanosine 3',5'-cyclic monophosphate (cGMP) or nitrate (NO2)/nitrite (NO3). Sodium nitroprusside (20 microg kg(-1) min(-1), i.v.) under the inhalation of halothane (2 vol%) increased the renal interstitial concentration of cGMP. L-Arginine (priming dose, 300 mg kg(-1) 10 min(-1); sustaining dose, 50 mg kg(-1) min(-1), i.v.) did not reverse halothane-induced reductions of cGMP and NO2/NO3. These findings demonstrate that halothane caused a renal vasoconstriction and inhibited the NO-guanylate cyclase signaling pathway in the kidney. Moreover, it is possible that the renal hemodynamic responses to halothane might have been induced, in part, through this inhibition. Finally, it can be assumed that halothane did not interfere with the activation process of guanylate cyclase by NO.

Redox control of Epstein-Barr virus replication by human thioredoxin/ATL-derived factor: differential regulation of lytic and latent infection

Human thioredoxin (hTRX)/adult T-cell leukemia (ATL)-derived factor (ADF) was originally reported as an interleukin-2 (IL-2) receptor-alpha-inducing factor produced by human T-cell lymphotropic virus-1-positive (HTLV-1+) cell lines. Growing evidence indicates that hTRX/ADF plays important roles in cellular responses against oxidative stress and is involved in a variety of cellular functions. A high level of hTRX/ADF expression is also observed in other human virus-infected cell lines including those of Epstein-Barr virus (EBV) and human papillomavirus. In this report, we analyzed the effect of hTRX/ADF on lytic amplification and persistent replication of EBV as a model for lytic versus latent phase of viral replication in host cells. Addition of hTRX/ADF clearly suppressed lytic replication of EBV in Raji cells and B95-8 cells induced to the lytic phase of 12-O-tetradecanoylphorbol-13-acetate (TPA), and it prevented the death of these cells evoked by the lytic induction. In contrast, hTRX/ADF did not have any effect on persistent replication in the latent phase. These data indicated that hTRX/ADF prevents EBV-transformed cells from proceeding into the lytic phase and regulates cohabitation of EBV and its host cells.

Glial progenitor cells in normal and pathological states

We have been studying glial progenitor cells by using antibodies against the NG2 proteoglycan and the alpha receptor for platelet-derived growth factor (PDGF alpha R). In vitro the two molecules are expressed on oligodendrocyte progenitor cells but are down-regulated as they differentiate into mature oligodendrocytes. In vivo, they are found not only during development but also exist abundantly throughout the gray and white matter of the mature brain and are distinct from astrocytes or microglia. A small fraction of NG2+ cells in the early postnatal brain differentiates into oligodendrocytes in vivo. We examined changes in NG2+/PDGF alpha R+ cells in the dysmyelinating mutant jimpy, which arises as a result of a point mutation in the proteolipid protein gene and is characterized by severe dysmyelination accompanied by premature oligodendrocyte death. In the spinal cords of jimpy mice at postnatal day 18, there was a three- to six-fold increase in the number of NG2+ glial cells that had incorporated bromodeoxyuridine compared with that in the wild type spinal cord. To identify signals responsible for the increased proliferation of oligodendrocyte progenitor cells, mRNAs isolated from jimpy and wild type mice were assayed for various cytokines. There was no significant change in the levels of PDGF A or TGF-beta, but there was a significant increase in the level of the chemokine GRO alpha in the jimpy spinal cord. We are currently testing the possibility that GRO alpha directly acts on glial progenitor cells and stimulates their proliferation.

Effects of thyroid status on expression of voltage-gated potassium channels in rat left ventricle

OBJECTIVE

Thyroid hormone modifies cardiac action potentials and outward potassium currents directly and indirectly e.g. through beta-adrenergic signaling pathway. We thus examined the expression of six voltage-gated potassium channel alpha-subunits in the rat left ventricle under hypo- and hyperthyroid status, and tested roles of beta-adrenergic signaling pathway in their expressions under both status.

METHODS

Hypothyroidism and hyperthyroidism were induced by administration of methimazole (MMI) for 4 weeks and by injection of L-thyroxine (T4) to the MMI-treated rats for the last 7 days, respectively. To distinguish the effects of T4 and the beta-adrenergic system, propranolol (Pro) was administered to the MMI-treated rats together with T4, and isoproterenol (Iso) was injected to MMI-treated rats for the last 7 days. The mRNA levels of Kv1.2, Kv1.4, Kv1.5, Kv2.1, Kv4.2 and Kv4.3 in the left ventricles were determined by ribonuclease protection assay.

RESULTS

MMI treatment induced hypothyroidism and resulted in a significant decrease in the mRNA levels of Kv1.5, Kv2.1 and Kv4.2 (19%, 77% and 61% of control value, respectively; n = 6, p < 0.05). T4 administration induced hyperthyroidism and cardiac hypertrophy, and it increased the Kv1.5 and Kv2.1 mRNA levels over the control value (212% and 140%, respectively; n = 6, p < 0.05). Kv4.2 mRNA level was restored to the control level by T4. In contrast, the Kv1.2 and Kv1.4 mRNA levels increased in hypothyroid rats (161% and 186% of control value, respectively; n = 6, p < 0.01) and decreased in hyperthyroid rats (14% and 33% of control value, respectively; n = 6, p < 0.01). The Kv4.3 mRNA level was not altered by thyroid status. Pro did not inhibit the T4-induced hypertrophy. Iso induced cardiac hypertrophy. Pro or Iso by itself did not alter Kv mRNA levels except for Kv1.2, the message of which was decreased by Iso.

CONCLUSION

Thyroid hormone differentially regulates the expression of Kv1.4, Kv1.5, Kv2.1 and Kv4.2 mRNA levels in the rat left ventricle. This effect is not mediated through beta-adrenergic signaling pathway. On the other hand, the reduction in Kv1.2 mRNA level was associated with cardiac hypertrophy induced by T4 or Iso.

Phosphorylation of LukS by protein kinase A is crucial for the LukS-specific function of the staphylococcal leukocidin on human polymorphonuclear leukocytes

Staphylococcal leukocidin (Luk) consists of two protein components, LukF and LukS, which cooperatively lyse human and rabbit polymorphonuclear leukocytes. Here, we demonstrate that the phosphorylation of LukS by protein kinase A is crucial for the LukS-specific leukocytolytic function of Luk on HPMNLs by using N-[2(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide (H-89), which is a potent and selective inhibitor of protein kinase A. At 0.5 microM H-89 completely prevented the Luk-induced cell lysis accompanied by blocking of the incorporation of exogenous 32P-H3PO4 into LukS on HPMNLs. However, with LukS and LukF together, 0.5 microM H-89 did not inhibit the cell swelling which takes place before the cell lysis. HPMNLs also became swollen upon treating with both LukF and LukS mutants which could not be phosphorylated.

Expression of thioredoxin is enhanced in atherosclerotic plaques and during neointima formation in rat arteries

Thioredoxin (TRX) is an intracellular enzyme that has a variety of activities as a hydrogen donor for various intracellular molecules. In the present study, we investigated the role of TRX in atherosclerotic lesions. In human atherosclerotic specimens, TRX and TRX mRNA were enhanced in endothelial cells and macrophages in the atherosclerotic plaques. In balloon-injured rat arteries, TRX expression increased from 2 to 6 weeks after injury; TRX was induced in the neointimal regenerating endothelial cells. In hybridization experiments, TRX mRNA was also induced from 2 to 6 weeks in the endothelium. In this model, inducible nitric oxide synthase immunoreactivity in the neointimal smooth muscle cells and endothelial cells increased from 2 to 6 weeks after surgical procedures were performed. During this period, the immunoreactivity of nitrotyrosine, which is a marker of nitric oxide (NO) production, also increased. We focused on the association between TRX and NO. In vitro studies using a murine endothelial cell line showed TRX and TRX mRNA induction by NO and peroxynitrite donors. Enhanced expression of TRX was detected mainly within the cytoplasm in immunocytochemical studies. In addition, TRX-transfected cells showed resistance to peroxynitrite-induced cytotoxicity. These findings indicate that TRX and the cellular redox state modified by TRX play a crucial role in arterial neointima formation in atherosclerosis.

Home blood pressure measurement has a stronger predictive power for mortality than does screening blood pressure measurement: a population-based observation in Ohasama, Japan

OBJECTIVE

To compare the predictive powers of self-measurement of blood pressure at home (home blood pressure measurement) and casual (screening) blood pressure measurement for mortality.

DESIGN

A prospective cohort study.

SUBJECTS AND METHODS

We obtained home and screening blood pressure measurements for 1789 subjects aged > or = 40 years who were followed up for a mean of 6.6 years. The prognostic significance of blood pressure for mortality was determined by the Cox proportional hazards regression model adjusted for age, sex, smoking status, past history of cardiovascular disease, and the use of antihypertensive medication.

RESULTS

When the home blood pressure values and the screening blood pressure values were simultaneously incorporated into the Cox model as continuous variables, only the average of multiple (taken more than three times) home systolic blood pressure values was significantly and strongly related to the cardiovascular mortality risk. The average of the two initial home blood pressure values was also better related to the mortality risk than were the screening blood pressure values.

CONCLUSIONS

Home blood pressure measurement had a stronger predictive power for mortality than did screening blood pressure measurement for a general population. This appears to be the first study in which the prognostic significances of home and screening blood pressure measurements have been compared.

Antisense telomerase treatment: induction of two distinct pathways, apoptosis and differentiation

Telomerase, the enzyme that elongates telomeric DNA (TTAGGG)n, may be involved in cellular immortality and oncogenesis. To investigate the effect of inhibition of telomerase on tumor cells, we transfected the antisense vector against the human telomerase RNA into human malignant glioma cells exhibiting telomerase activity. After 30 doublings, some subpopulations of transfectants expressed a high level of interleukin-1beta-converting enzyme (ICE) protein and underwent apoptosis. In contrast, other subpopulations also showed enhanced ICE protein but escaped from apoptotic crisis and continued to grow, although their DNA synthesis, invasive ability, and tumorigenicity in nude mice were significantly reduced. Surviving cells demonstrated increased expression of glial fibrillary acidic protein and decreased motility, consistent with a more differentiated state. These cells also contained enhanced expression of the cyclin-dependent kinase inhibitors (CDKIs) p21 and p27. Treatment of surviving nonapoptotic cells with antisense oligonucleotides against p27, but not p21, induced apoptotic cell death, suggesting that p27 may have protected differentiating glioma cells from apoptosis. These data show that treatment with antisense telomerase inhibits telomerase activity and subsequently induces either apoptosis or differentiation. Regulation of these two distinct pathways may be dependent on the expression of ICE or CDKIs.