[Pulmonary embolism due to right atrial large thrombus quickly disappeared by intravneous thrombolysis].
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Aged↗
Biomedical subjects
T Ohtomo
Publications and source records attributed to T Ohtomo.
Information circulation in a two-mode solid-state laser with optical feedback.
A two-mode solid-state laser subjected to a delayed optical feedback is studied. Simultaneous random switchings between stable and chaotic antiphase spiking oscillations featuring the establishment of causal (drive response) relationships among modes have been demonstrated by a proposed information circulation analysis of an experimental time series. The observed phenomenon has been well reproduced by numerical simulations of two-mode laser equations with uncorrelated modal phase fluctuations.
Journal Article↗
An evolutionarily conserved motif in the TAB1 C-terminal region is necessary for interaction with and activation of TAK1 MAPKKK.
TAK1, a member of the MAPKKK family, is involved in the intracellular signaling pathways mediated by transforming growth factor beta, interleukin 1, and Wnt. TAK1 kinase activity is specifically activated by the TAK1-binding protein TAB1. The C-terminal 68-amino acid sequence of TAB1 (TAB1-C68) is sufficient for TAK1 interaction and activation. Analysis of various truncated versions of TAB1-C68 defined a C-terminal 30-amino acid sequence (TAB1-C30) necessary for TAK1 binding and activation. NMR studies revealed that the TAB1-C30 region has a unique alpha-helical structure. We identified a conserved sequence motif, PYVDXA/TXF, in the C-terminal domain of mammalian TAB1, Xenopus TAB1, and its Caenorhabditis elegans homolog TAP-1, suggesting that this motif constitutes a specific TAK1 docking site. Alanine substitution mutagenesis showed that TAB1 Phe-484, located in the conserved motif, is crucial for TAK1 binding and activation. The C. elegans homolog of TAB1, TAP-1, was able to interact with and activate the C. elegans homolog of TAK1, MOM-4. However, the site in TAP-1 corresponding to Phe-484 of TAB1 is an alanine residue (Ala-364), and changing this residue to Phe abrogates the ability of TAP-1 to interact with and activate MOM-4. These results suggest that the Phe or Ala residue within the conserved motif of the TAB1-related proteins is important for interaction with and activation of specific TAK1 MAPKKK family members in vivo.
Amino Acid Motifs↗
Percutaneous ulnar artery approach for coronary angiography: a preliminary report in nine patients.
The radial artery approach is becoming more popular for diagnostic cardiac catheterization and interventional procedures because of its lower incidence of access site complications and decreased patient discomfort after the procedure. However, Allen's test reveals inadequate blood supply through the ulnar artery to the hand, and therefore the approach does not seem to be suitable in 10%-30% of patients. Here we demonstrated a new percutaneous ulnar artery approach for coronary angiography in nine patients. We succeeded in obtaining an entry site into the left ulnar artery in seven patients. The average time for cannulation and that for catheterization procedure were comparable with those of the radial approach previously reported from other laboratories. Complications such as bleeding, loss of an ulnar pulse, ulnar nerve injury, and the formation of an aneurysm or fistula were not observed in any patient. The ulnar approach may be another technique that decreases patient discomfort and risk, while preserving the radial artery as a potential coronary bypass graft for surgical myocardial revascularization. Cathet Cardiovasc Intervent 2001;53:410-414.
Adult↗
Prevalence of asymptomatic ST segment elevation in right precordial leads with right bundle branch block (Brugada-type ST shift) among the general Japanese population.
OBJECTIVE: To examine the modality and morbidity of asymptomatic ST segment elevation in leads V1 to V3 with right bundle branch block (Brugada-type ST shift). METHODS: 8612 Japanese subjects (5987 men and 2625 women, mean age 49.2 years) who underwent a health check up in 1997 were investigated. Those with Brugada-type ST shift underwent the following further examinations over a two year period after the initial check up: ECG, echocardiogram, 24 hour Holter monitoring, treadmill exercise testing, signal averaged ECG, and slow kinetic sodium channel blocker loading test (cibenzoline, 1.4 mg/kg). RESULTS: Asymptomatic Brugada-type ST shift was found in 12 of 8612 (0.14%) subjects. Eleven of these 12 subjects were followed up. Follow up ECG exhibited persistent Brugada-type ST shift in seven of 11 (63.6%) subjects. ST shift was transformed from a saddle back to a coved type in three subjects. None of the subjects had morphological abnormalities or abnormal tachyarrhythmias. Positive late potentials were found in seven of 11 (63.6%) subjects. Augmentation of ST shift was shown by both submaximal exercise and drug administration in one of the 11 subjects (9.1%). CONCLUSIONS: Asymptomatic subjects with Brugada-type ST shift were not unusual, at a rate of 0.14% in the general Japanese population. Almost all of the subjects had some abnormalities in non-invasive secondary examinations. Additional and prospective studies are needed to confirm the clinical significance and the prognosis of asymptomatic Brugada-type ST shift.
Adult↗
Case of transient erythroblastopenia of childhood with transient hypogammaglobulinemia.
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Agammaglobulinemia↗
Molecular cloning and characterization of a surface antigen preferentially overexpressed on multiple myeloma cells.
HM1.24 antigen has been identified as a surface molecule preferentially expressed on terminally differentiated B cells, and its overexpression is observed in multiple myeloma cells. The HM1.24 antigen is, therefore, expected as a most potent target molecule for antibody-based immunotherapy for multiple myeloma. Here, we have identified the cDNA for human HM1.24 antigen and also analyzed its gene structure including the promoter region. The HM1.24 antigen is a type II membrane glycoprotein, which has been reported as a bone marrow stromal cell surface antigen BST2, and may exist as a homodimer on myeloma cell surface. Although a reason for the overexpression in myeloma cells is not understood, very interestingly, the promoter region of the HM1.24 gene has a tandem repeat of three cis elements for a transcription factor, STAT3, which mediates interleukin-6 (IL-6) response gene expression. Since IL-6 is a differentiation factor for B cells, and known as a paracrine/autocrine growth factor for multiple myeloma cells, the expression of HM1.24 antigen may be regulated by the activation of STAT3. Importantly, a humanized anti-HM1.24 antibody effectively lysed the CHO transformants which expressed HM1.24 antigen as high as human multiple myeloma cells, but not the cells with lower antigen expression. This evaluation shows that ADCC heavily depends on the expression level of target antigens and, therefore, the immunotherapy targeting the HM1.24 antigen should have a promising potential in clinical use.
Amino Acid Sequence↗
The humanized anti-HM1.24 antibody effectively kills multiple myeloma cells by human effector cell-mediated cytotoxicity.
A mouse monoclonal antibody, anti-HM1.24 (IgG2a/kappa), binds to a surface antigen preferentially overexpressed on multiple myeloma (MM) cells, and exhibits potent antitumor cell activity against MM cells by antibody-dependent cell-mediated cytotoxicity (ADCC). To develop an antibody-based immunotherapy against MM, a humanized anti-HM1.24 antibody, in which all FRs correspond to naturally processed human FRs, has been successfully constructed with the aid of both the hybrid variable region and two-step design methods. This humanized anti-HM1.24 antibody (IgG1/kappa) is able to effectively induce ADCC against human myeloma KPMM2 and ARH77 cells in the presence of human PBMCs as effectively as a chimeric anti-HM1.24 antibody. The humanized anti-HM1.24 antibody, therefore, could be expected as a potent immunotherapeutic agent for MM patients.
Amino Acid Sequence↗
Some biochemical properties of the components of Staphylococcus aureus binding to human platelets.
The binding properties of Staphylococcus aureus in relation to human platelets were investigated. Protease digestion (pronase E, proteinase K, trypsin), heat treatment (80 degrees C, 30 min), and sonication for 5 min significantly reduced the binding abilities of the staphylococcal cells to 0% (p < .01), 50 +/- 5% (p < .05), and 38 +/- 9% (p < .05), respectively, while mixed glycosidases did not. Inhibition experiments indicated that protein A and various sugars were ineffective. A binding study using biotinylated cell surface fractions extracted from the whole cells of S. aureus indicated that the proteins having apparent molecular weights of 14400 and 16500 estimated by sodium dodecylsulfate-polyacrylamide gel electrophoresis were involved in the binding between S. aureus and human platelets.
Bacterial Adhesion↗
[A 29-year-old man with diabetes insipidus and cerebellar ataxia and development of spinal cord swelling 15 years after the onset].
We report a 29-year-old man with diabetes insipidus and cerebellar ataxia who developed spinal cord swelling 15 years after the onset. He was well until 14 years of the age when he noted dizziness. Two years after there was an onset of gait disturbance and slurred speech. He also noted polydipsia and polyuria. He was evaluated at the neurosurgery service of our hospital when he was 17 years of the age. Neurologic examination at that time revealed memory loss, horizontal nystagmus, cerebellar ataxic gait, dysmetria and decomposition more on the left. Cranial CT scan revealed a mass lesion involving the left subthalamic region and the head of the caudate area. Spinal fluid was unremarkable, however, human chorionic gonadotropin was increased to 27 mIU/ml. He was treated by radiation therapy (3,000 rads for total brain area and 5,460 rads for focal region). His CT scan and memory loss improved, however, cerebellar ataxia was unchanged. Three years after the radiation, he started to show choreic movement in his neck and left upper extremity. He was admitted to our service in August 14, 1995 when he was 29 years of the age. On admission, he was alert but disoriented to time; calculation was also poor. Higher cerebral functions were intact. The optic fundi were normal without papilledema. Visual field appeared intact. Gaze nystagmus was observed in all the directions, but more prominent in the horizontal direction. Speech was slurred. Otherwise, cranial nerves were unremarkable. Motor wise, he showed marked truncal and gait ataxia; he was unable to walk because of ataxia. Muscle atrophy and marked weakness was noted in both upper extremities more on the left side. Deep tendon reflexes were diminished in the upper extremities but active in the lower extremities. He was polyuric; urinary specific gravity was low. Spinal fluid contained 6 cells/cmm and 113 mg/ dl of protein; Queckenstedt was positive. MRI revealed swelling of the cervical cord; in addition, the entire cervical region and the medullar oblongata appeared as high signal intensity areas. No mass lesion was noted in the supratentorial structures but the third ventricle was markedly enlarged. Surgical biopsy was performed on the cervical lesion. The patient was discussed in neurologic CPC, and the chief discussant arrived at the conclusion that the patient had germinoma with syncytiotrophoblastic giant cells in the diencephalic region which appeared to have been cured by radiation therapy; he thought that the cervical lesion was the seeding of germinoma. Cerebellar ataxia was ascribed to the remote effect of germinoma. Most of the participants thought that the original tumor was germinoma and the cervical lesion was its spread. Some participants thought that his ataxia was caused by germinoma cells involving the medulla and the inferior cerebellar peduncles. Histologic observation of the biopsied tissue from the spinal cord revealed the typical two cell patterned germinoma. Most of the tumor cells were not stained for an antibody against HCG, but some tumor cells were positively stained. Germinoma is very radio-sensitive; this patient showed T2 high signal lesion involving the medulla oblongata and cervical cord continuously. Probably, tumor cells in the lower brain stem escaped radiation, and gradually spread to the spinal cord over many years. At the time of operation, the surface of the spinal cord was free from tumor cells. Therefore, tumor cells invaded the spinal cord continuously from the medulla oblongata. He was treated with cervical radiation, and his neurologic as well as radiologic findings showed marked improvement.
Adult↗
Down-regulation of telomerase activity is an early event in the differentiation of HL60 cells.
Telomerase has been shown to be essential for unlimited cell proliferation and has been linked to immortality. However, still very little is known about the mechanism by which this enzyme is activated or inactivated. To investigate its regulation, we closely monitored telomerase activity during HL60 cell differentiation induced by either 1 alpha,25-dihydroxyvitamin D3 or all-trans retinoic acid. To that effect, we used a new combination of TRAP assay and SPA, which provides reproducible data for the quantitation and detection of variations in enzyme activity. We thereby observed that the decrease in telomerase activity after induction of differentiation by either of these agents is an early event of the differentiation process rather than its consequence, and that it is independent of the growth arrest pathway. It is neither due to a reduced expression of its RNA component nor to the appearance of a telomerase inhibitor in differentiating cells but is parallel to an increase in p21 and Rb mRNA expression.
Base Sequence↗
Mouse MCM proteins: complex formation and transportation to the nucleus.
BACKGROUND: The members of the MCM protein family, including MCM2, MCM3, Cdc21, CDC46, Mis5 and CDC47, are considered to be involved in the control of a single round of DNA replication during S phase in eukaryotes. They bind to chromatin during G1 and detach from it during S phase as if they license the chromatin to replicate. However, unlike the originally proposed 'licensing factor' and the budding yeast homologues, mammalian MCM2 and P1MCM3 proteins appeared to be localized in the nucleus during the interphase. RESULTS: We purified mCdc21 and its associated proteins from mouse cell extract by anti-mCdc21 immunoaffinity chromatography. Three proteins which co-purified with mCdc21 were identified as mCDC47, mMis5 and mMCM2, all were MCM proteins. Glycerol gradient centrifugation analysis showed that all the mouse MCM proteins were detected at 450-600 kDa, an indication of the sum of their calculated molecular weights from their amino acid sequences. mCdc21 was displaced from replicated chromatin in a similar way to P1MCM3 and MCM2 during S phase. Among the six mouse MCM proteins, only mMCM2 and mP1MCM3 showed nuclear localization when overexpressed in COS cells. CONCLUSIONS: We conclude that in the mouse, six MCM proteins form a single protein complex of molecular weight 450-600 kDa, which may enter the nucleus by nuclear localization signals in the mMCM2 and mP1MCM3 subunits.
Amino Acid Sequence↗
[A 32-year-old man who developed a posterior fossa mass 12 years after the radiation therapy for cerebellar arteriovenous malformation].
We report a 32-year-old man who developed cerebellar ataxia and a posterior fossa mass 12 years after the radiation therapy for a cerebellar arteriovenous malformation (AVM). The patient was well until 19 years of the age when he had an acute onset of vertigo and vomiting. A spinal tap was performed and the CSF was bloody. He was admitted to another hospital where an arteriovenous malformation was found in the cerebellum by angiography. Four years after the onset, he developed tingling sensation in the distribution of the second division of the right trigeminal nerve. He was admitted to the neurosurgery service of our hospital where the cerebellar AVM was confirmed. He was transferred to University of California where Bragg peak stereotaxic radiotherapy was successfully performed; this utilizes high energy alpha-ray produced by a cyclotron. Three years after the radiotherapy, marked reduction in the size of the AVM was confirmed by angiography. Twelve years after the onset of his initial symptom, he noted unsteadiness of gait. He was readmitted to our neurosurgery service where obstructive hydrocephalus was found. He was treated by ventriculoperitoneal shunting and placement of a Ommaya reservoir. After these therapy, he noted marked improvement in his gait and ataxia. However, in 1993, his unsteadiness of gait recurred, and he was again admitted to our neurosurgery service on June 20, 1993. On admission, T1-weighted MRI revealed a slightly low signal intensity mass lesion in the right cerebellar hemisphere compressing the brain stem; a spotty high signal intensity lesion and another small low intensity lesion were seen within the mass. Vertebro-basilar angiograms revealed upward displacement of the superior cerebellar arteries. No arteriovenous nidus was visualized. On July, 3rd, the cyst was surgically drained and the Ommaya reservoir was removed. Post-operative course was uneventful, however, he developed head tremor after the surgery. Neurologic examination on July 20, 1993 revealed an alert and well oriented man in no acute distress. General physical examination was unremarkable. Neurologic examination revealed no dementia; higher cerebral functions appeared intact. The optic discs were flat, and visual fields were intact. Ocular movements were full but convergence was restricted. Horizontal gaze nystagmus was noted more in the right lateral gaze. Pupils were intact. Facial sensation and facial muscles were intact. Hearing was normal. His voice was of nasal quality. Pharyngeal reflex was diminished. The tongue showed deviation to the left without atrophy. Head tremor at 5 c/s was noted. He was able to stand with support but was unable to walk. No muscle atrophy or weakness was noted. The finger-to-nose and the heel-to-knee tests showed dysmetria and decomposition more on the right. Rapid alternating movements were ataxic on the right. Muscle tone was diminished on the right. Muscle stretch reflexes were normally elicited and were symmetric. The plantar response was flexor bilaterally. Sensation was intact. On July 21, a posterior fossa exploration was performed. After the surgery, he was treated with 30 mg/day of alotinolol which showed no effect on his head tremor. He was then treated with gradually increasing doses of clonazepam; when he received 8 mg/day of clonazepam, his tremor showed marked improvement. He was discussed in a neurologic CPC on the nature of the posterior fossa lesion and his tremor. Opinions were divided between delayed radiation necrosis and a radiation-induced brain tumor. The chief discussant arrived at the conclusion that the patient had delayed radiation necrosis compressing the brain stem and cerebellar hemispheres. Regarding the nature of his tremor, he thought that his head tremor was of cerebellar type of postural tremor. Histologic examination of the biopsied specimen revealed accumulation of relatively fresh blood constituents in the deep area of the cerebellum forming a mass. Most of the
Adult↗
Transport of levofloxacin in a kidney epithelial cell line, LLC-PK1: interaction with organic cation transporters in apical and basolateral membranes.
The interactions of levofloxacin, a pyridonecarboxylic acid antibacterial drug, with the organic cation transport systems expressed in a pig kidney epithelial cell line, LLC-PK1, were examined. The transcellular transport of tetraethylammonium was remarkably inhibited by levofloxacin, accompanied by a marked increase in the cellular accumulation of tetraethylammonium in the LLC-PK1, monolayers grown on collagen-coated membrane filters. The results obtained by efflux and uptake of tetraethylammonium revealed that levofloxacin drastically inhibited the apical transport activity rather than the basolateral uptake of tetraethylammonium. Under conditions in which the apical efflux of tetraethylammonium was blocked by pretreatment with p-chloromercuribenzene sulfonate, levofloxacin showed a moderate inhibitory effect against the basolateral uptake of tetraethylammonium. Transepithelial flux of levofloxacin from the basolateral side to the apical side was much greater than the flux in the opposite direction. The flux of levofloxacin was influenced by the apical side pH, resulting in a decreased cellular accumulation by lowering pH. The basal-to-apical transport and cellular accumulation of levofloxacin were not inhibited by either tetraethylammonium or cimetidine. These results suggested that levofloxacin interacts with the apical H+/organic cation antiport system to a greater extent than with the basolateral system. However, transcellular transport of levofloxacin would be mediated by the transport systems which are distinct from the systems for tetraethylammonium in LLC-PK1 cells.
Cell Line↗
Na(+)-dependent uptake of 1,5-anhydro-D-glucitol via the transport systems for D-glucose and D-mannose in the kidney epithelial cell line, LLC-PK1.
1,5-Anhydro-D-glucitol, a 1-deoxy form of D-glucose, is one of the major polyols in human and rat blood plasma, and is regarded as a sensitive marker of glycemic control in diabetic patients. Although renal tubular reabsorption of 1,5-anhydro-D-glucitol is thought to maintain the physiological plasma level of this polyol, the mechanism of its cellular uptake has not yet been established. In the present study, the transport characteristics of 1,5-anhydro-D-glucitol in a kidney epithelial cell line, LLC-PK1, were investigated. The uptake of 1,5-anhydro-D-glucitol by the LLC-PK1 cell monolayers was found to be a highly Na(+)-dependent process. The initial uptake rate of 1,5-anhydro-D-glucitol was inhibited by the presence of D-glucose, D-mannose and methyl-alpha-D-glucoside, a nonmetabolizable D-glucose analogue. D-Mannose was taken up partially by LLC-PK1 cells in a Na(+)-dependent manner. 1,5-Anhydro-D-glucitol had an inhibitory effect on the uptake of both methyl-alpha-D-glucoside and D-mannose. Phlorizin inhibited the uptake of methyl-alpha-D-glucoside and 1,5-anhydro-D-glucitol, but not of D-mannose. In contrast, phloretin inhibited the uptake of both 1,5-anhydro-D-glucitol and D-mannose, but not the uptake of methyl-alpha-D-glucoside. The apparent Michaelis-Menten constant and maximum velocity values for 1,5-anhydro-D-glucitol uptake were 29 mM and 240 pmol/mg protein/min, respectively. These findings suggest that the uptake of 1,5-anhydro-D-glucitol across the apical membranes of LLC-PK1 cells is mediated by the Na(+)/D-glucose cotransport system and probably by the Na+/D-mannose cotransport system.
Animals↗
[Fatty heart, myocardial fatty infiltration].
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Cardiomyopathies↗
Humanization of an anti-human IL-6 mouse monoclonal antibody glycosylated in its heavy chain variable region.
Interleukin-6 (IL-6) inhibitors are good potential therapeutic agents in human patients, and anti-IL-6 antibodies are among the best candidates. Here, we have successfully humanized mouse monoclonal antibody SK2, which specifically binds to IL-6 and strongly inhibits IL-6 functions. Since this antibody possesses N-linked carbohydrates on Asn-30 of VH region, which seems to be very close to an antigen-binding site, influence of these carbohydrates on antigen-binding was investigated. A biosensor study showed that the mouse SK2 Fab and its deglycosylated fragments had almost equal Kd (Kon/Koff), 26.8 nM (1.05 x 10(6)/2.81 x 10(-2)) and 24.7 nM (1.28 x 10(6)/3.15 x 10(-2)), respectively. Furthermore, a mutant chimeric SK2 antibody, in which the N-glycosylation site was removed from the VH region, showed a Kd of 11 nM, almost similar to that of the original chimeric SK2 antibody, determined by Scatchard analysis with 125I-IL-6. These data indicate the carbohydrates of mouse SK2 VH region do not significantly influence antigen-binding activity. In the next step, two versions of each humanized SK2 VL and VH regions were carefully designed based on the amino acid sequences of human REI and DAW, respectively. Only one alteration, Tyr to Phe, was made at position 71 in the two light chains, according to the canonical residue for LI. A N-glycosylation site was introduced on the two heavy chains, by changing Ser to Asn at position 30. All four combinations of humanized light and heavy chains could bind to IL-6 as well as the chimeric SK2 antibody. The light chain first version, however, could not efficiently inhibit IL-6 binding to its receptor, indicating the importance of the LI loop conformation for the inhibitory activity of SK2 antibody. In contrast, both versions of the heavy chains were comparable, in yielding good humanized SK2 antibodies, suggesting that the glycosylation of the SK2 VH region has no influence in recreating a functional antigen-binding site in this humanization.
Amino Acid Sequence↗
Myasthenia gravis, acute transverse myelitis, and HTLV-I.
We present the unusual case of a 49-year-old female carrier of HTLV-I with myasthenia gravis who presented with acute transverse myelitis. Laboratory data suggested a recent infection with varicella zoster virus and demyelination by an autoimmune process in the central nervous system. Adult T-cell leukemia-like cells were observed in the cerebrospinal fluid. T-cell-mediated immune responses modulated by HTLV-I infection may be involved in the pathogenesis of myasthenia gravis and acute transverse myelitis in this case.
Acute Disease↗