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1.
Nat Commun ; 14(1): 733, 2023 Feb 09.
Article in English | MEDLINE | ID: mdl-36759612

ABSTRACT

Superconductivity in the cuprates is found to be intertwined with charge and spin density waves. Determining the interactions between the different types of order is crucial for understanding these important materials. Here, we elucidate the role of the charge density wave (CDW) in the prototypical cuprate La1.885Sr0.115CuO4, by studying the effects of large magnetic fields (H) up to 24 Tesla. At low temperatures (T), the observed CDW peaks reveal two distinct regions in the material: a majority phase with short-range CDW coexisting with superconductivity, and a minority phase with longer-range CDW coexisting with static spin density wave (SDW). With increasing magnetic field, the CDW first grows smoothly in a manner similar to the SDW. However, at high fields we discover a sudden increase in the CDW amplitude upon entering the vortex-liquid state. Our results signify strong coupling of the CDW to mobile superconducting vortices and link enhanced CDW amplitude with local superconducting pairing across the H - T phase diagram.

2.
J Hand Surg Eur Vol ; 42(9): 896-902, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28610452

ABSTRACT

We report on the outcomes of flexor tendon repair in zone 2 subzones with early active mobilization in 102 fingers in 88 consecutive patients. There were 28, 53, 15, and six fingers with repairs in zones 2A to 2D, respectively. Rupture of the repair occurred in four fingers, all in zone 2B. Excluding those with repair ruptures, the mean total active motion was 230° (range 143°-286°). Evaluated with Tang's criteria, the outcomes were ranked excellent in 39 fingers, good in 46, fair in ten, poor in three, and failure in four. The outcomes in zone 2C were significantly inferior to those in zones 2B and 2D ( p = 0.02). Our results suggest that the tendon laceration in the area covered by the A2 pulley (zone 2C) is the most difficult area to obtain satisfactory active digital motion and tendon repair in zone 2B is the area where the risk of rupture is highest. LEVEL OF EVIDENCE: IV.


Subject(s)
Finger Injuries/rehabilitation , Finger Injuries/surgery , Tendon Injuries/rehabilitation , Tendon Injuries/surgery , Adolescent , Adult , Aged , Aged, 80 and over , Child , Exercise Therapy , Female , Humans , Male , Middle Aged , Range of Motion, Articular , Recovery of Function , Retrospective Studies , Suture Techniques , Sutures , Treatment Outcome , Young Adult
3.
Proc Natl Acad Sci U S A ; 113(51): 14645-14650, 2016 12 20.
Article in English | MEDLINE | ID: mdl-27930313

ABSTRACT

The existence of charge-density-wave (CDW) correlations in cuprate superconductors has now been established. However, the nature of the CDW ground state has remained uncertain because disorder and the presence of superconductivity typically limit the CDW correlation lengths to only a dozen unit cells or less. Here we explore the field-induced 3D CDW correlations in extremely pure detwinned crystals of YBa2Cu3O2 (YBCO) ortho-II and ortho-VIII at magnetic fields in excess of the resistive upper critical field ([Formula: see text]) where superconductivity is heavily suppressed. We observe that the 3D CDW is unidirectional and possesses a long in-plane correlation length as well as significant correlations between neighboring CuO2 planes. It is significant that we observe only a single sharply defined transition at a critical field proportional to [Formula: see text], given that the field range used in this investigation overlaps with other high-field experiments including quantum oscillation measurements. The correlation volume is at least two to three orders of magnitude larger than that of the zero-field CDW. This is by far the largest CDW correlation volume observed in any cuprate crystal and so is presumably representative of the high-field ground state of an "ideal" disorder-free cuprate.

4.
Oral Dis ; 22(6): 557-65, 2016 Sep.
Article in English | MEDLINE | ID: mdl-27087630

ABSTRACT

OBJECTIVES: The aims of this study were to investigate the prevalence of sleep bruxism in children in Japan, and its relationships with sleep-related factors and daytime problematic behavior. SUBJECTS AND METHODS: Guardians of 6023 children aged 2-12 years completed the Japanese Sleep Questionnaire. Multiple regression analysis and structural equation modeling were performed. RESULTS: Sleep bruxism was reported in 21.0% children (n = 1263): the prevalence was highest in the age group of 5-7 years (27.4%). Multiple regression analysis showed that sleep bruxism had significant correlations with age 5-7 years (OR: 1.72; P < 0.0001), 'Moves a lot during sleep' (OR: 1.47; P < 0.0001), 'sleeps with mouth open' (OR: 1.56; P < 0.0001), and 'snores loudly' (OR: 1.80; P < 0.0001). In structural equation modeling, sleep bruxism had a significant but weak direct effect on daytime problematic behavior, while sleep bruxism significantly correlated with obstructive sleep apnea, which had a higher direct effect on daytime problematic behavior. CONCLUSIONS: Sleep bruxism was reported in 21.0% of Japanese children and had independent relationships with age, movements during sleep, and snoring. A comorbidity of sleep-disordered breathing might be related to daytime problematic behavior in children with sleep bruxism.


Subject(s)
Child Behavior Disorders/complications , Sleep Apnea Syndromes/complications , Sleep Bruxism/complications , Age Factors , Child , Child, Preschool , Humans
5.
Science ; 350(6263): 949-52, 2015 Nov 20.
Article in English | MEDLINE | ID: mdl-26541608

ABSTRACT

Charge density wave (CDW) correlations have been shown to universally exist in cuprate superconductors. However, their nature at high fields inferred from nuclear magnetic resonance is distinct from that measured with x-ray scattering at zero and low fields. We combined a pulsed magnet with an x-ray free-electron laser to characterize the CDW in YBa2Cu3O6.67 via x-ray scattering in fields of up to 28 tesla. While the zero-field CDW order, which develops at temperatures below ~150 kelvin, is essentially two dimensional, at lower temperature and beyond 15 tesla, another three-dimensionally ordered CDW emerges. The field-induced CDW appears around the zero-field superconducting transition temperature; in contrast, the incommensurate in-plane ordering vector is field-independent. This implies that the two forms of CDW and high-temperature superconductivity are intimately linked.

6.
Arzneimittelforschung ; 62(12): 545-53, 2012 Dec.
Article in English | MEDLINE | ID: mdl-22945770

ABSTRACT

A combination of low-dose aspirin (ASA) and a phosphodiesterase inhibitor has been clinically tried for the secondary prevention of atherothrombotic diseases. The in vivo antithrombotic property of ibudilast (CAS 50847-11-5), a phosphodiesterase 4 (PDE4) inhibitor, was evaluated in a photochemically-induced guinea pig carotid artery thrombosis model in combination with low-dose ASA. The time required to decrease the carotid artery blood flow to the reading "zero" was defined as the time to occlusion (TTO) of the artery through thrombogenesis. Each independent use of ASA (300 mg/kg, p.o.) and ibudilast (3 and 10 mg/kg, p.o.) significantly prolonged the TTO, and ASA (300 mg/kg) significantly increased bleeding time (BT) and gastric mucosal injury. A selective PDE4 inhibitor rolipram (1 and 5 mg/kg, p.o.) tended to prolong the TTO without extending BT. ASA (100 mg/kg) plus ibudilast (3 mg/kg) and ASA (100 mg/kg) plus rolipram (5 mg/kg) markedly prolonged the TTO compared with each agent alone. Interestingly, ASA (100 mg/kg) plus ibudilast (3 mg/kg) caused a longer TTO than ASA (300 mg/kg) alone, without significant extension of BT and gastric mucosal injury as observed in ASA (300 mg/kg). These results indicate that the combination of low-dose ASA and ibudilast has a more potent antithrombotic effect than ASA alone without increasing bleeding tendency and gastric mucosal injury. The potent in vivo antithrombotic effect of this combination may be brought about by an action that is associated with PDE4 inhibition of ibudilast.


Subject(s)
Aspirin/therapeutic use , Carotid Artery Thrombosis/prevention & control , Gastric Mucosa/pathology , Phosphodiesterase Inhibitors/therapeutic use , Platelet Aggregation Inhibitors/therapeutic use , Pyridines/therapeutic use , Stomach Diseases/chemically induced , 6-Ketoprostaglandin F1 alpha/metabolism , Animals , Aspirin/adverse effects , Aspirin/blood , Bleeding Time , Drug Therapy, Combination , Guinea Pigs , Immunoenzyme Techniques , Indicators and Reagents , Male , Mice , Phosphodiesterase Inhibitors/adverse effects , Phosphodiesterase Inhibitors/blood , Photochemistry , Platelet Aggregation Inhibitors/adverse effects , Platelet Aggregation Inhibitors/blood , Pyridines/adverse effects , Pyridines/blood , Rolipram/therapeutic use , Salicylic Acid/blood , Stomach Diseases/pathology , Thromboxane B2/metabolism
8.
J Laryngol Otol ; 124(12): 1340-3, 2010 Dec.
Article in English | MEDLINE | ID: mdl-20537211

ABSTRACT

OBJECTIVE: Small cell carcinoma has the worst prognosis of all laryngeal neoplasms. In order to further characterise this tumour, with a view to development of new therapeutic approaches, we report the results of KIT gene and platelet-derived growth factor receptor α gene expression analysis, for two extremely rare cases of primary small cell carcinoma of the larynx. METHOD: Case reports, including immunohistochemical study, and review of the literature. RESULTS: We present two patients with laryngeal small cell carcinoma, who died from tumour metastasis to the lungs and brain despite aggressive treatment. Immunohistochemical studies revealed positive reactions for KIT gene expression and platelet-derived growth factor α gene expression in patient one, and for KIT gene expression in patient two. Molecular genetic analysis, using polymerase chain reaction direct sequencing, identified no mutations of the KIT or platelet-derived growth factor receptor α genes. CONCLUSION: Although further investigation is necessary regarding KIT gene expression and platelet-derived growth factor receptor α gene expression in laryngeal small cell carcinoma, the reported results suggest that these genes may be significant in the development of molecular targeted therapy.


Subject(s)
Carcinoma, Small Cell/genetics , Laryngeal Neoplasms/genetics , Platelet-Derived Growth Factor/genetics , Proto-Oncogene Proteins c-kit/genetics , Aged , Brain Neoplasms/secondary , Carcinoma, Small Cell/secondary , Combined Modality Therapy , Fatal Outcome , Gene Expression Profiling , Humans , Immunohistochemistry , Lung Neoplasms/secondary , Male , Molecular Targeted Therapy
9.
Kyobu Geka ; 61(5): 375-8, 2008 May.
Article in Japanese | MEDLINE | ID: mdl-18464482

ABSTRACT

Patients with advanced non-small cell lung cancer invading a chest wall are surgical candidates if complete resection is possible. When a primary tumor locating the lower lobe invades an inferior chest wall, either a wide skin incision or double skin incisions to secure surgical views both for dissection of hilum and mediastinum and for inferior chest wall resection is necessary. Wider incision causes higher rate of wound necrosis and infection. We describe a combined approach of thoracoscopic and open chest surgery for lobectomy and inferior chest wall resection, respectively. Patient was a 68-year-old man with an advanced non-small cell lung cancer. Video-assisted thoracoscopic middle and lower lobectomies and mediastinal nodal dissection was completed via 5 ports. Chest wall resection including the posterior portion of the 9th and 10th ribs and the transverse process followed inferior postero-lateral thoracotomy. Postoperative course was uneventful. The present surgical approach can avoid a wide thoracotomy for an advanced lung cancer invading an inferior chest wall.


Subject(s)
Carcinoma, Non-Small-Cell Lung/surgery , Lung Neoplasms/surgery , Pneumonectomy/methods , Thoracic Surgery, Video-Assisted/methods , Thoracic Wall/surgery , Thoracotomy/methods , Aged , Carcinoma, Non-Small-Cell Lung/pathology , Combined Modality Therapy , Humans , Lung Neoplasms/pathology , Male , Neoplasm Invasiveness , Neoplasm Staging , Thoracic Neoplasms/pathology , Thoracic Neoplasms/surgery , Treatment Outcome
10.
Oncogene ; 27(25): 3527-38, 2008 Jun 05.
Article in English | MEDLINE | ID: mdl-18223693

ABSTRACT

Overexpression of S100A7 (psoriasin), a small calcium-binding protein, has been associated with the development of psoriasis and carcinomas in different types of epithelia, but its precise functions are still unknown. Using human tissue specimens, cultured cell lines, and a mouse model, we found that S100A7 is highly expressed in preinvasive, well-differentiated and early staged human squamous cell carcinoma of the oral cavity (SCCOC), but little or no expression was found in poorly differentiated, later-staged invasive tumors. Interestingly, our results showed that S100A7 inhibits both SCCOC cell proliferation in vitro and tumor growth/invasion in vivo. Furthermore, we demonstrated that S100A7 is associated with the beta-catenin complex, and inhibits beta-catenin signaling by targeting beta-catenin degradation via a noncanonical mechanism that is independent of GSK3beta-mediated phosphorylation. More importantly, our results also indicated that beta-catenin signaling negatively regulates S100A7 expression. Thus, this reciprocal negative regulation between S100A7 and beta-catenin signaling implies their important roles in tumor development and progression. Despite its high levels of expression in early stage SCCOC tumorigenesis, S100A7 actually inhibits SCCOC tumor growth/invasion as well as tumor progression. Downregulation of S100A7 in later stages of tumorigenesis increases beta-catenin signaling, leading to promotion of tumor growth and tumor progression.


Subject(s)
Calcium-Binding Proteins/metabolism , Carcinoma, Squamous Cell/metabolism , Gene Expression Regulation, Neoplastic , Mouth Neoplasms/metabolism , beta Catenin/metabolism , Animals , Carcinoma, Squamous Cell/pathology , Cell Line, Tumor , Cell Proliferation , Disease Progression , Humans , Mice , Models, Biological , Mouth Neoplasms/pathology , Neoplasm Transplantation , S100 Calcium Binding Protein A7 , S100 Proteins , Signal Transduction
11.
Int J Gynecol Cancer ; 14(5): 1018-23, 2004.
Article in English | MEDLINE | ID: mdl-15361218

ABSTRACT

BACKGROUND: Small cell carcinoma of the endometrium is extremely rare. Aim. We reported three cases of this rare tumor and reviewed the literature. CASES: Case 1 was a 54-year-old woman and case 3 was a 58-year-old woman. Both patients presented with vaginal bleeding. Case 2, a 53-year-old woman, had no symptoms and had a vaginal-cervical smear suspicious for malignancy. All patients underwent surgery and their tumors originated in the endometrium. In all three cases, pathological examination revealed small cell carcinoma of endometrium, and immunohistochemical reactivity for one or more neuroendocrine markers was found in all cases. Under electron microscopy in case 2 and case 3, dense core granules in the cytoplasm of tumor cells were found only in case 3. Case 3 was stage IIIA and died of her disease 12 months after surgery. Both cases 1 and 2 were stage IB and alive with no evidence of disease for 28 months and 9 years, respectively. CONCLUSION: Although the prognosis of small cell carcinoma of endometrium is poor, early detection of this disease may contribute to an improved prognosis.


Subject(s)
Carcinoma, Small Cell/pathology , Carcinoma, Small Cell/surgery , Endometrial Neoplasms/pathology , Endometrial Neoplasms/surgery , Disease-Free Survival , Female , Humans , Immunohistochemistry , Microscopy, Electron , Middle Aged , Prognosis , Uterine Hemorrhage/etiology
12.
Environ Sci Technol ; 35(15): 3139-43, 2001 Aug 01.
Article in English | MEDLINE | ID: mdl-11505989

ABSTRACT

To clarify the photolytic behavior of polycyclic aromatic hydrocarbons (PAHs) in diesel particulate matter (DPM) deposited on the ground, we determined the rate constants and half-lives for the photodegradation of benzo[a]pyrene (BaPy), phenanthrene (Phe), fluoranthene (Flrt), pyrene (Py), and chrysene (Ch) in air for three probable cases: (1) DPM is placed on an inert surface, (2) DPM is mixed with soil, and (3) PAHs are leached from DPM and adsorbed to soil. We found that BaPy and Phe degraded relatively quickly in case 1. However, in case 2, these PAHs degraded more slowly due to the effect of the presence of soil. Flrt, Py, and Ch were stable. In case 3, photodegradation of adsorbed PAHs in soil was strongly inhibited as a function of soil depth. Although these findings were obtained at extreme light intensities, they may occur under real world conditions. Conversion factors for obtaining rate constants and half-lives for PAHs on the ground under sunlight are presented. We conclude that under the average intensity of sunlight in Tokyo, photodegradation of PAHs in DPM deposited on an inert surface is very slow.


Subject(s)
Air Pollutants/analysis , Polycyclic Aromatic Hydrocarbons/chemistry , Vehicle Emissions/analysis , Environmental Monitoring , Half-Life , Particle Size , Photolysis , Soil , Sunlight
13.
Mol Cell ; 7(5): 915-26, 2001 May.
Article in English | MEDLINE | ID: mdl-11389839

ABSTRACT

Destruction of beta-catenin is regulated through phosphorylation-dependent interactions with the F box protein beta-TrCP. A novel pathway for beta-catenin degradation was discovered involving mammalian homologs of Drosophila Sina (Siah), which bind ubiquitin-conjugating enzymes, and Ebi, an F box protein that binds beta-catenin independent of the phosphorylation sites recognized by beta-TrCP. A series of protein interactions were identified in which Siah is physically linked to Ebi by association with a novel Sgt1 homolog SIP that binds Skp1, a central component of Skp1-Cullin-F box complexes. Expression of Siah is induced by p53, revealing a way of linking genotoxic injury to destruction of beta-catenin, thus reducing activity of Tcf/LEF transcription factors and contributing to cell cycle arrest.


Subject(s)
Calcium-Binding Proteins , Carrier Proteins/physiology , Cell Cycle Proteins , Cytoskeletal Proteins/metabolism , Drosophila Proteins , GTP-Binding Proteins , Heat-Shock Proteins , Insect Proteins/physiology , Nuclear Proteins/physiology , Trans-Activators , Tumor Suppressor Protein p53/pharmacology , Amino Acid Sequence , Cell Cycle/drug effects , Cytoskeletal Proteins/drug effects , DNA Damage/physiology , DNA-Binding Proteins/drug effects , DNA-Binding Proteins/metabolism , Humans , Insect Proteins/metabolism , Insect Proteins/pharmacology , Lymphoid Enhancer-Binding Factor 1 , Molecular Sequence Data , Nuclear Proteins/metabolism , Nuclear Proteins/pharmacology , Protein Binding , Sequence Alignment , Signal Transduction/drug effects , Transcription Factors/drug effects , Transcription Factors/metabolism , Tumor Cells, Cultured , Tumor Suppressor Protein p53/physiology , Two-Hybrid System Techniques , Ubiquitin-Protein Ligases , beta Catenin
14.
J Biol Chem ; 276(34): 32220-9, 2001 Aug 24.
Article in English | MEDLINE | ID: mdl-11408476

ABSTRACT

Caspase-associated recruitment domains (CARDs) are protein interaction domains that participate in activation or suppression of CARD-carrying members of the caspase family of apoptosis-inducing proteases. A novel CARD-containing protein was identified that is overexpressed in some types of cancer and that binds and suppresses activation of procaspase-9, which we term TUCAN (tumor-up-regulated CARD-containing antagonist of caspase nine). The CARD domain of TUCAN selectively binds itself and procaspase-9. TUCAN interferes with binding of Apaf1 to procaspase-9 and suppresses caspase activation induced by the Apaf1 activator, cytochrome c. Overexpression of TUCAN in cells by stable or transient transfection inhibits apoptosis and caspase activation induced by Apaf1/caspase-9-dependent stimuli, including Bax, VP16, and staurosporine, but not by Apaf1/caspase-9-independent stimuli, Fas and granzyme B. High levels of endogenous TUCAN protein were detected in several tumor cell lines and in colon cancer specimens, correlating with shorter patient survival. Thus, TUCAN represents a new member of the CARD family that selectively suppresses apoptosis induced via the mitochondrial pathway for caspase activation.


Subject(s)
Adaptor Proteins, Signal Transducing , Apoptosis , Neoplasm Proteins/metabolism , Amino Acid Sequence , Apoptotic Protease-Activating Factor 1 , Base Sequence , CARD Signaling Adaptor Proteins , Caspase 9 , Caspase Inhibitors , Caspases/metabolism , DNA Primers , Enzyme Activation , Enzyme Precursors/antagonists & inhibitors , Enzyme Precursors/metabolism , Humans , Immunohistochemistry , Jurkat Cells , Models, Molecular , Molecular Sequence Data , Neoplasm Proteins/chemistry , Neoplasm Proteins/genetics , Neoplasms/enzymology , Protein Binding , Protein Conformation , Proteins/chemistry , Sequence Homology, Amino Acid
15.
Br J Ophthalmol ; 85(2): 130-3, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11159472

ABSTRACT

BACKGROUND/AIMS: Diagnosis of ocular tuberculosis is difficult, particularly the retinal vasculitis type, because most cases occur without concurrent active pulmonary tuberculosis. Recently, it has been reported that detection of antibodies against purified cord factor (trehalose-6,6'-dimycolate, TDM), the best studied, most antigenic, and most abundant cell wall component of tubercule bacilli, is very useful for rapid serodiagnosis of pulmonary tuberculosis. In this study, an attempt was made to evaluate whether the detection of anticord factor antibody is also useful for diagnosis of ocular tuberculosis and the necessity of antituberculous therapy for tuberculous retinochoroiditis was discussed. METHODS: Cases consisted of 15 patients with uveitis and retinal vasculitis, nine patients with presumed ocular tuberculosis, three patients with sarcoidosis, and three patients with Behçet's disease. IgG antibodies against purified cord factor prepared from Mycobacterium tuberculosis H37Rv were detected by enzyme linked immunosorbent assay. RESULTS: All cases of clinically presumed ocular tuberculosis were positive, whereas all of the cases of sarcoidosis or Behçet's disease were negative for anticord factor antibodies. When the anticord factor antibody titres were compared on the basis of the presence or absence of previous antituberculosis chemotherapy, the mean anticord factor antibody titre of the untreated group showed a tendency to be higher than in the treated group, but not significantly (p=0.07). CONCLUSIONS: The detection of anticord factor antibody may be useful to support the diagnosis of ocular tuberculosis. Additionally, a positive result for anticord factor antibody may indicate that tubercule bacilli are present in some organ(s) of the patient even in the absence of active systemic disease.


Subject(s)
Antigens, Bacterial/immunology , Cord Factors/immunology , Mycobacterium tuberculosis/immunology , Tuberculosis, Ocular/diagnosis , Adult , Aged , Antibodies, Bacterial/blood , Behcet Syndrome/diagnosis , Diagnosis, Differential , Enzyme-Linked Immunosorbent Assay/methods , Female , Humans , Immunoglobulin G/blood , Male , Middle Aged , Retinal Diseases/diagnosis , Retinal Diseases/therapy , Retinal Vein , Sarcoidosis/diagnosis , Tuberculosis, Ocular/immunology , Tuberculosis, Ocular/therapy , Uveitis, Anterior/diagnosis , Uveitis, Anterior/therapy , Vasculitis/diagnosis , Vasculitis/therapy
16.
J Biol Chem ; 276(11): 8087-93, 2001 Mar 16.
Article in English | MEDLINE | ID: mdl-11098060

ABSTRACT

TRAF family proteins are signal-transducing adapter proteins that interact with the cytosolic domains of tumor necrosis factor (TNF) family receptors. Here we show that TRAF1 (but not TRAF2-6) is cleaved by certain caspases in vitro and during TNF-alpha- and Fas-induced apoptosis in vivo. (160)LEVD(163) was identified as the caspase cleavage site within TRAF1, generating two distinct fragments. Significant enhancement of TNF receptor-1 (CD120a)- and, to a lesser extent, Fas (CD95)-mediated apoptosis was observed when overexpressing the C-terminal TRAF1 fragment in HEK293T and HT1080 cells. The same fragment was capable of potently suppressing TNF receptor-1- and TRAF2-mediated nuclear factor-kappaB activation in reporter gene assays, providing a potential mechanism for the enhancement of TNF-mediated apoptosis. Cell death induced by other death receptor-independent stimuli such as cisplatin, staurosporine, and UV irradiation did not result in cleavage of TRAF1, and overexpression of the C-terminal TRAF1 fragment did not enhance cell death in these cases. TRAF1 cleavage was markedly reduced in cells that contain little procaspase-8 protein, suggesting that this apical protease in the TNF/Fas death receptor pathway is largely responsible. These data identify TRAF1 as a specific target of caspases activated during TNF- and Fas-induced apoptosis and illustrate differences in the repertoire of protease substrates cleaved during activation of different apoptotic pathways.


Subject(s)
Apoptosis , Caspases/metabolism , Proteins/metabolism , Tumor Necrosis Factor-alpha/physiology , Female , Humans , Lymphocyte Activation , Lymphocytes/metabolism , NF-kappa B/metabolism , TNF Receptor-Associated Factor 1 , Tumor Cells, Cultured , fas Receptor/physiology
17.
J Radiat Res ; 41(2): 113-27, 2000 Jun.
Article in English | MEDLINE | ID: mdl-11037579

ABSTRACT

Following the exposure of mice to X rays or fission neutrons, the frequency (F) of apoptosis was measured after 4 h, and the weight loss or lymphocyte content loss in the thymus and spleen was measured after 24 h. In p53(+/+) mice, F increased linearly with the dose (D (Gy)) and the induced rate per Gy of F (detected by TUNEL staining) was 0.05 and 0.23 for X rays and fission neutrons, respectively. Therefore, the RBE of fission neutrons was 4.6 for apoptosis induction. This indicates that radiation-induced apoptosis is mostly due to double strand breaks (DSBs) in DNA because we previously obtained almost the same RBE value of fission neutrons for the induction of crossover mutations in Drosophila melanogaster, which arise from the recombinational repair of DSBs. In p53(+/+) mice, decreases in the organ weight and the lymphocyte content were observed for the thymus and the spleen 24 h after X-irradiation. These atrophic changes in the thymus and the spleen quantitatively corresponded to the total apoptotic cell deaths occurring in them. However, in p53(-/-) mice, no vigorous apoptosis was induced after X-irradiation, and hyperplastic changes in the weight and the lymphocyte content appeared in the thymus and the spleen 24 h after X-irradiation. In p53(+/+) mice, there was no difference in the induced rate per Gy of reduction in the surviving fraction of lymphocytes between acute (0.4 Gy/min) and chronic (3 mGy/min) gamma-irradiations. Namely, radiation-induced apoptosis in lymphocytes is a dose-rate independent event.


Subject(s)
Apoptosis/radiation effects , Fast Neutrons , Gamma Rays , Genes, p53 , Lymphocytes/radiation effects , Radiation Tolerance/genetics , Spleen/radiation effects , Thymus Gland/radiation effects , Tumor Suppressor Protein p53/physiology , Animals , Apoptosis/genetics , Atrophy , DNA Damage , Dose-Response Relationship, Radiation , Female , Lymphocyte Count , Lymphocytes/cytology , Mice , Mice, Inbred C57BL , Mice, Inbred ICR , Mice, Knockout , Organ Size/radiation effects , Organ Specificity , Radiation Injuries, Experimental/pathology , Relative Biological Effectiveness , Spleen/pathology , Thymus Gland/pathology , Tumor Suppressor Protein p53/deficiency , Weight Loss/radiation effects , X-Rays
18.
J Exp Med ; 191(10): 1709-20, 2000 May 15.
Article in English | MEDLINE | ID: mdl-10811864

ABSTRACT

Reportedly, antiapoptotic Bcl-2 family proteins suppress apoptosis by binding to and inhibiting members of the CED-4 family of caspase activators. To explore this question, we used embryonic stem (ES) cells in which one (-/+) or both (-/-) copies of the gene encoding apoptotic protease activating factor 1 (Apaf-1), a CED-4 homologue, were disrupted by homologous recombination. Stable clones of heterozygous (-/+) and homozygous (-/-) Apaf-1 knockout ES cells that overexpressed Bcl-2 were generated. Withdrawal of serum growth factors or stimulation of heterozygous ES cells with staurosporine (STS), ultraviolet (UV)B irradiation, etoposide (VP16), or cisplatin induced apoptosis followed by cell death (determined by failure to exclude propidium iodide dye). These cell death stimuli also induced activation of several types of caspases and loss of mitochondrial membrane potential (DeltaPsi) in heterozygous (+/-) Apaf-1 knockout ES cells. In addition, overexpression of Bcl-2 protected against these events in Apaf-1-expressing ES cells. In contrast, STS, UVB, and VP16 induced little or no caspase activation and apoptosis in homozygous (-/-) Apaf-1 knockout ES cells. Nevertheless, Apaf-1-deficient ES cells subjected to these cell death stimuli or deprived of growth factors did eventually die through a nonapoptotic mechanism associated with loss of DeltaPsi. Moreover, Bcl-2 overprotection preserved DeltaPsi, reduced the percentage of Apaf-1(-/)- ES cells undergoing cell death, and increased clonigenic survival. The extent of Bcl-2-mediated cytoprotection was not significantly different for heterozygous (-/+) versus homozygous (-/-) Apaf-1 knockout cells. Furthermore, although Bcl-2 could be readily coimmunoprecipitated with Bax, associations with Apaf-1 were undetectable under conditions where Apaf-1 interactions with procaspase-9 were observed. We conclude that Bcl-2 has cytoprotective functions independent of Apaf-1, preserving mitochondrial function through a caspase-independent mechanism.


Subject(s)
Apoptosis/physiology , Proteins/genetics , Proteins/physiology , Proto-Oncogene Proteins c-bcl-2/physiology , Amino Acid Sequence , Animals , Antineoplastic Agents/pharmacology , Apoptosis/genetics , Apoptosis/radiation effects , Apoptotic Protease-Activating Factor 1 , Caspases/metabolism , Cell Death/genetics , Cell Death/physiology , Cell Death/radiation effects , Clone Cells , Enzyme Activation , Gene Expression , Genes, bcl-2 , Mice , Mice, Knockout , Microscopy, Electron , Oligopeptides/chemistry , Proto-Oncogene Proteins/metabolism , Proto-Oncogene Proteins c-bcl-2/genetics , Stem Cells/cytology , Stem Cells/physiology , Substrate Specificity , Ultraviolet Rays , bcl-2-Associated X Protein
19.
J Biol Chem ; 275(16): 12102-7, 2000 Apr 21.
Article in English | MEDLINE | ID: mdl-10766844

ABSTRACT

A member of the tumor necrosis factor (TNF) receptor-associated factor (TRAF) family was identified in Drosophila. DTRAF1 contains 7 zinc finger domains followed by a TRAF domain, similar to mammalian TRAFs and other members of the family identified in data bases from Caenorhabditis elegans, Arabidopsis, and Dictyostelium. Analysis of DTRAF1 binding to different members of the human TNF receptor family showed that this protein can interact through its TRAF domain with the p75 neurotrophin receptor and weakly with the lymphotoxin-beta receptor. DTRAF1 can also self-associate and binds to human TRAF1, TRAF2, and TRAF4. Interestingly, DTRAF1 interacts with human cIAP-1 and cIAP-2 but not with Drosophila DIAP-1 and -2. By itself, DTRAF1 did not induce significant NFkappaB activation when overexpressed in mammalian cells, although it specifically increased NFkappaB induction by TRAF6. In contrast, TRAF2-mediated NFkappaB induction was partially inhibited by DTRAF1. Mutants of DTRAF1 lacking the N-terminal region inhibited NFkappaB induction by either TRAF2 or TRAF6. DTRAF1 specifically associated with the regulatory N-terminal domain of Pelle, a Drosophila homolog of the human kinase interleukin-1 receptor-associated kinase (IRAK). Interestingly, though Pelle and DTRAF1 individually were unable to induce NFkappaB in a human cell line, co-expression of Pelle and DTRAF1 resulted in significant NFkappaB activity. Interactions of DTRAF1 with human TRAF-, TNF receptor-, and IAP-family proteins imply strong evolutionary conservation of TRAF protein structure and function throughout Metazoan evolution.


Subject(s)
Drosophila Proteins , Drosophila/metabolism , NF-kappa B/metabolism , Protein Serine-Threonine Kinases/metabolism , Proteins/metabolism , Amino Acid Sequence , Animals , Arabidopsis , Caenorhabditis elegans , Dictyostelium , Humans , Interleukin-1 Receptor-Associated Kinases , Molecular Sequence Data , Protein Binding , Protein Kinases/metabolism , Receptors, Interleukin-1/metabolism , TNF Receptor-Associated Factor 1 , TNF Receptor-Associated Factor 2 , TNF Receptor-Associated Factor 4 , Tumor Necrosis Factor Receptor-Associated Peptides and Proteins , Zinc Fingers
20.
J Biol Chem ; 275(20): 15578-85, 2000 May 19.
Article in English | MEDLINE | ID: mdl-10747903

ABSTRACT

Expression of heat shock proteins (HSPs) is controlled by heat shock transcription factors (HSFs). Vertebrates express multiple HSFs whose activities may be regulated by distinct signals. HSF3 is specifically activated in unstressed proliferating cells by direct binding to the c-myb proto-oncogene product (c-Myb), which plays an important role in cellular proliferation. This suggests that the c-Myb-induced HSF3 activation may contribute to the growth-regulated expression of HSPs. Here we report that the p53 tumor suppressor protein directly binds to HSF3 and blocks the interaction between c-Myb and HSF3. In addition, p53 stimulates the degradation of c-Myb through a proteasome-dependent mechanism, which is, at least partly, mediated by induction of Siah in certain types of cells. Induction of p53 by a genotoxic reagent in DT40 cells disrupts the HSF3-c-Myb interaction and down-regulates the expression of certain HSPs. Mutated forms of p53 found in certain tumors did not inhibit c-Myb-induced HSF3 activation. The regulation of HSF3 activity by c-Myb and p53 sheds light on the molecular events that govern HSP expression during cellular proliferation and apoptosis.


Subject(s)
Avian Proteins , DNA-Binding Proteins/metabolism , Proto-Oncogene Proteins c-myb/metabolism , Trans-Activators/metabolism , Tumor Suppressor Protein p53/metabolism , Animals , Cell Line , Chickens , Cysteine Endopeptidases/metabolism , Genes, Reporter , Heat-Shock Proteins/metabolism , Humans , Kinetics , Luciferases/genetics , Mice , Multienzyme Complexes/metabolism , Mutagenesis, Site-Directed , Point Mutation , Proteasome Endopeptidase Complex , Proto-Oncogene Mas , Proto-Oncogene Proteins c-myb/antagonists & inhibitors , Recombinant Proteins/metabolism , Transcription, Genetic , Transfection
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