Edge states of Floquet-Dirac semimetal in a laser-driven semiconductor quantum-well.

Band crossings observed in a wide range of condensed matter systems are recognized as a key to understand low-energy fermionic excitations that behave as massless Dirac particles. Despite rapid progress in this field, the exploration of non-equilibrium topological states remains scarce and it has potential ability of providing a new platform to create unexpected massless Dirac states. Here we show that in a semiconductor quantum-well driven by a cw-laser with linear polarization, the optical Stark effect conducts bulk-band crossing, and the resulting Floquet-Dirac semimetallic phase supports an unconventional edge state in the projected one-dimensional Brillouin zone under a boundary condition that an electron is confined in the direction perpendicular to that of the laser polarization. Further, we reveal that this edge state mediates a transition between topological and non-topological edge states that is caused by tuning the laser intensity. We also show that the properties of the edge states are strikingly changed under a different boundary condition. It is found that such difference originates from that nearly fourfold-degenerate points exist in a certain intermediate region of the bulk Brillouin zone between high-symmetry points.

Laser-controlled exciton Fano resonance in semiconductor superlattices.

Quantum control of excitonic Floquet states in semiconductor superlattices driven by an intense monochromatic laser is examined from a theoretical point of view. High-resolution optical absorption spectra, calculated using multichannel scattering theory with the R-matrix propagation method, clarified that the excitonic Fano resonance structure is induced by the laser field. Each of the physical quantities related to this resonance-such as the spectral intensity, an asymmetry parameter (q-parameter), a resonance width, and so on-shows a characteristic extremum as a function of laser strength (F(ac)) in the vicinity of a critical value of F(ac) where dynamic localization is realized. It has also been shown that this F(ac)-dependence is caused by an ac-Zener coupling between two photon sidebands. Further, we have shown that these quantities are also controlled by changing the laser frequency (ω), as well as F(ac), and the underlying physics is explained on the basis of anticrossing behavior of the two photon sidebands.

[Our current technique for basic pterional craniotomy].

Pterional cnaniotomy is frequently used in neurosurgical practice, but still poses significant cosmetic and functional drawbacks. Here, we describe our modified technique to overcome such problems as the sterilization of the scalp without brush and razor, preemptive analgesia, preservation of the periostium for reconstruction, retrograde dissection of the temporal muscle, and complete sphenoidotomy using chisel or drills. The tips of our pterional craniotomy offer suitable size and depth of working field around the paraclinoidal regions, maintaining cosmetic satisfaction of the patients.

Meningeal melanocytoma associated with ipsilateral nevus of Ota presenting as intracerebral hemorrhage: case report.

OBJECTIVE AND IMPORTANCE: The authors report a rare case of meningeal melanocytoma presenting with unconsciousness, which was caused by an intracerebral hematoma and associated with a history of ipsilateral nevus of Ota. CLINICAL PRESENTATION: A 75-year-old woman developed nevus of Ota in the first and second divisions of the right trigeminal nerve territory, which had been treated with a skin graft 40 years earlier. She noticed right exophthalmos but left it untreated for 2 years and then became comatose owing to orbital and intracranial tumors, the latter manifesting with hemorrhage. INTERVENTION: She underwent craniotomy, during which the tumor was partially removed with intracerebral hematoma. Histopathologically, the tumor was diagnosed as meningeal melanocytoma. Western blot analysis demonstrated a retained protein expression of cell cycle inhibitor p16(INK4A) and a high level of antiapoptotic Bcl-2 in the resected tumor. CONCLUSION: The combination of nevus of Ota and meningeal melanocytoma has been reported in only four cases in the literature, including the current case. This is the first case coinciding with intracerebral hemorrhage, suggesting the necessity for careful follow-up with radiological images.

Morphologic changes in neo-intimal proliferation in an experimental aneurysm after coil embolization: effect of factor XIII administration.

We investigated histological changes in aneurysmal orifices after embolization with Guglielmi detachable coils (GDCs) and determined the effects of the wound-healing factor, factor XIII, on promoting intimal proliferation by scanning electron microscopy (SEM). GDC embolization was performed in an experimental model of aneurysm in swine. In the control group (17 aneurysms), the aneurysms were resected immediately after surgery, at 1 and 3 weeks after the procedure. In the factor XIII-administered group (13 aneurysms), the swine received factor XIII postoperatively, and the aneurysms were excised at 1 and 3 weeks. The endothelial cell proliferation changes in the aneurysm orifices in both groups were evaluated by SEM. The histological changes at the orifices began immediately after the procedure, and endothelialization was observed at 1 week. One week after the procedure, the rate of endothelial cell proliferation was significantly higher in the factor XIII group (P<0.05). But no difference was observed at 3 weeks, when endothelialization of the orifices was essentially completed. The process of intimal proliferation after coil embolization was similar to the wound-healing process after vascular intimal injury. Administration of the wound-healing factor, factor XIII, would contribute rapid intimal proliferation and may be effective to facilitate complete obliteration of aneurysms after coil embolization.

[Hepatitis-associated aplastic anemia preceded by a hemophagocytic syndrome-like state].

A 21-year-old man was admitted to our hospital for acute hepatitis of unknown cause. His liver function improved with rest, but worsened 2 months later. He developed a high fever and pancytopenia. The serum level of cytokines including TNF-alpha, IFN-gamma, IL-6, and M-CSF was elevated, and hemophagocytes were seen in bone marrow. These findings suggested a hemophagocytic syndrome-like state. With prednisolone, gamma-globulin, and G-CSF, the high fever disappeared and the patient's liver function gradually recovered. However, the severe pancytopenia persisted. The bone marrow became acellular with a small number of hemophagocytes, and hepatitis-associated aplastic anemia was diagnosed. After immunosuppressive therapy with ATG, CyA and G-CSF was started, and the patient showed hematopoietic reconstitution. The bone marrow CD4+/CD8+ lymphocyte ratio recovered to within the normal range, and the serum cytokines including TNF-alpha and IFN-gamma decreased. The increase in serum cytokines, particularly TNF-alpha and INF-gamma, as well as the presence of activated T cells associated with the preceding hemophagocytic syndrome-like state may have predisposed this patient to aplastic anemia.

[Acute myeloid leukemia originating from the same leukemia clone after the complete remission of acute lymphoid leukemia].

A 22-year-old female was diagnosed as having acute lymphoid leukemia (ALL) in February 1995, from the findings of peroxidase negative, CD10+, CD19+, TdT+ and rearrangement of IgH and TCR beta. AdVP (doxorubicin, vincristine and prednisolone) therapy achieved a complete remission (CR). Bone marrow transplantation had to be abandoned because of the lack of an HLA-identical donor. Intensification therapy was thus carried out repeatedly. In June 1998, myeloblast with Auer rods, peroxidase positive, CD13+, CD33+ and HLA-DR+, appeared. The patient was diagnosed as having lineage switch acute myeloid leukemia (AML) from ALL. Though A-DMP (cytosine arabinoside, daunorubicin, 6-mercaptopurine) therapy was resistant, AdVP therapy led to a CR. The patient died of cardiotoxicity from anthracyclines in February 1999. From the results of the Ramasamy method using the clonal rearrangements of the Ig heavy chain gene locus, the origin of the pathological cells of ALL and AML was indicated to be the same leukemia clone.

[Severe type of Epstein-Barr virus associated hemophagocytic syndrome successfully treated with T-COP-E and splenectomy].

A 16-year-old girl was admitted to our hospital because of high fever, abdominal pain, and jaundice. Abnormal lymphocytes and hemophagocytic cells had infiltrated the bone marrow. Laboratory data revealed a severe type of hemophagocytic syndrome accompanied by an initial Epstein-Barr virus (EBV) infection. Persistent EBV infection was identified by polymerase chain reaction (PCR) detection of EBV-DNA in peripheral blood and bone marrow mononuclear cells. The limited efficacy of initial treatment with high-dose gamma-globulin, plasmapheresis, and high-dose methylprednisolone prompted us to administration of T-COP-E (VP-16). Two courses of T-COP-E improved the patient's clinical symptoms and laboratory data; however, marked splenomegaly remained. In addition, fever and serum increase of lactate dehydrogenase (LDH) and cytokines such as gamma-interferon recurred shortly after chemotherapy. On day 53 after diagnosis, the patient underwent laparoscopic splenectomy. The resected spleen weighted 420 g and abnormal lymphocytes in the spleen were positive for CD 8 and negative for CD 56. In situ hybridization revealed EBV-encoded small RNAs (EBERs) in the abnormal lymphocytes. Clinical symptoms including high fever disappeared shortly after the splenectomy, and laboratory data returned to normal. Lymphocytosis after the splenectomy was not observed. We continued out patient monitoring of the case, and 16 months after diagnosis, EBV-DNA in peripheral blood mononuclear cells was not detected, even by PCR.

De novo dissecting aneurysm in a patient with a ruptured saccular lesion. Case report.

Formation of a new saccular aneurysm after successful treatment of ruptured aneurysm has recently raised significant clinical concerns; however, de novo formation and rupture of a dissecting aneurysm has not been discussed. The authors report on a 42-year-old man who initially sought treatment for a ruptured saccular aneurysm of the right middle cerebral artery, which was successfully eliminated by surgical clipping of the aneurysm neck. Two years later, the patient presented with another subarachnoid hemorrhage and was found to have a dissecting aneurysm of the right vertebral artery, which arose from a previously angiographically documented normal artery. This rare association sheds light on the causes and growth of two distinct types of aneurysms, both clinically and pathologically.

[Primary subcutaneous mantle cell lymphoma treated successfully with THP-COP therapy].

A 73-year-old man noticed a subcutaneous tumor on the left upper palpebra from April 1998, but did not seek therapy for it. Facial subcutaneous tumors appeared from November 1999, and multiple tumors appeared on the skin of the chest and both upper arms from January 2000. Tumor biopsy revealed that these tumors were non-Hodgkin lymphoma showing CD19 (+), CD20 (+), CD5 (+), CD10 (-), smIgM (+), sm lambda (+) and cyclin D1 (+). The karyotype was t(11;14) (q13;q32), but bcl-1 gene rearrangement was not detected. On the basis of these data, primary mantle cell lymphoma (MCL) of the subcutis was diagnosed. The patient underwent eight courses of THP-COP therapy, and complete remission was achieved. Primary subcutaneous B-cell lymphoma, especially MCL, is rare. MCL is aggressive and difficult to cure; the median survival of patients is 3 to 5 years, and the 5-year survival is 30%. However, the present patient showed a good response to chemotherapy, and complete remission has continued for 17 months since the MCL was first diagnosed.

Role of MmTRA1b/phospholipid scramblase1 gene expression in the induction of differentiation of human myeloid leukemia cells into granulocytes.

OBJECTIVE: We previously cloned a human normal counterpart (MmTRA1b/phospholipid scramblase 1) of the mouse leukemogenesis-associated gene MmTRA1a. MmTRA1b gene expression was increased during differentiation of human monoblastic leukemia U937 cells using some differentiation inducers but not 1alpha,25-dihydroxyvitamin D(3) (a typical monocytic differentiation inducer). To further elucidate the role of human MmTRA1b gene expression in the differentiation of myelogenous leukemia cells, we measured MmTRA1b gene expression in several myeloid leukemia cell lines and primary leukemia cells. MATERIALS AND METHODS: The expression of MmTRA1b mRNA was determined by semiquantitative reverse transcriptase polymerase chain reaction. RESULTS: Expression of the MmTRA1b gene was markedly induced during granulocytic differentiation of promyelocytic leukemia NB4 and HT93 cells induced by all-trans retinoic acid (ATRA). The level of MmTRA1b mRNA was significantly increased during differentiation toward granulocytes, but not monocytes/macrophages, in bipotential myeloid leukemia HL-60 cells. The level of MmTRA1 mRNA was not increased during erythroid differentiation induced by hemin in erythroid leukemia K562 and HEL cells or during megakaryocytic differentiation induced by 12-O-tetradecanoylphorbol-13-acetate in K562 cells. Expression of the MmTRA1b gene also was not induced when apoptosis of NB4 cells was induced by antileukemic drugs. ATRA-induced differentiation of antisense MmTRA1b-transfected NB4 cells was significantly suppressed. On the other hand, ATRA induced the differentiation of MmTRA1b-transfected NB4 cells more efficiently than that of mock-transfected cells. MmTRA1b mRNA also was clearly induced in ATRA-treated primary acute promyelocytic leukemia cells during granulocytic differentiation. CONCLUSION: MmTRA1b mRNA was specifically induced during granulocytic differentiation of acute promyelocytic leukemia cells and was associated with induction of their differentiation.