An Analytical Mass Spectrometer for the Gas Analysis

The tentative construction of a mass spectrometer of π/2 (Hipple type) single magnetic focusing to be used for the gas analysis is described in this paper. The mass scanning circuit contains a new electronic device replacing the mechanically driven scanner which has ever been used. For the analytical works, due emphasis should be given to the maintenance of the overall stability of the instruments for a long period of time. However, some analytical results are reported prior to this routine analysis and also the effects of the electron emitter treatment for the stabilization of the sensitivity and the cracking patterns (mass spectra) are discussed

Turbulent Structures in Unsteady Open-Channel Flows

Turbulence measurements over a smooth wall in unsteady open-channel flows were conducted accurately by the simultaneous use of a two-component LDA system and water-wave gauges. The “ general ” log-law distributions, in which the von Karman constant is a universal one of χ=0.41 but the integration constant A is a function of main-flow conditions, were obeyed well in the wall region for both the rising and falling stages of flood. On the other hand, the log-wake law was reasonably applied to the outer region including the depth-varying zone. The Coles' wake parameter Π increased for the rising stage, whereas it decreased for the falling stage. The turbulence is stronger for the rising stage than for the falling stage, except for very near the free surface. These unsteady characteristics in open-channel flows with variation of the water surface are quite different from those in closed duct flows. Of particular significance is the findings counterclockwise loops of velocity and turbulence against the varying depth in unsteady open-channel flows

A primary thymic adenocarcinoma with two components that traced distinct evolutionary trajectories

Even though it is a rare subtype, identifying the genetic features of thymic adenocarcinoma is valuable for a multifaceted understanding of thymic epithelial tumors. We experienced a female patient with thymic adenocarcinoma associated with thymic cysts. The tumor consisted of a solid whitish lesion (lesion-1) and a large cystic lesion with small papillary nodules (lesion-2). Microscopically, lesion-1 exhibited poorly differentiated adenocarcinoma accompanying numerous inflammatory cell infiltrates, and lesion-2 (the nodules within the cystic lesion) exhibited enteric-type adenocarcinoma. Consistent with the histological difference, whole-exome sequencing revealed that these two components exhibited distinct genetic features, except for only a few shared mutations, including CDKN2A truncation. Lesion-1 exhibited microsatellite instability-high signature with high mutation burden, for which immune checkpoint inhibitors might apply; and lesion-2 exhibited whole-genome doubling with KRAS hotspot mutation. Our case presents novel genetic features of thymic adenocarcinoma and demonstrates that distinct mutational processes can be operative within a single tumor

A case of Langerhans cell sarcoma on the scalp: Whole‐exome sequencing reveals a role of ultraviolet in the pathogenesis

Langerhans cell sarcoma (LCS) is a high‐grade neoplasm with overtly malignant cytological features and a Langerhans cell phenotype. The underlying genetic features are poorly understood, and only a few alterations, such as those of the MARK pathway‐related genes, CDKN2A and TP53 have been reported. Here we present a 70‐year‐old male with LCS on the scalp and pulmonary metastasis. The multinodular tumor, 3.0 cm in diameter, consisted of diffusely proliferated pleomorphic cells with numerous mitoses (53/10 HPFs). Immunohistochemically, the tumor cells were positive for CD1a, Langerin and PD‐L1, and the Ki‐67 labeling index was 50%. These pathological features were consistent with LCS, and were also observed in the metastatic tumor. Whole‐exome sequencing revealed that both the primary and metastatic tumors harbored a large number of mutations (>20 mutations/megabase), with deletion of CDKN2A and TP53 mutation, and highlighted that the mutational signature was predominantly characteristic of ultraviolet (UV) exposure (W = 0.828). Our results suggest, for the first time, that DNA damage by UV could accumulate in Langerhans cells and play a role in the pathogenesis of LCS. The high mutational burden and PD‐L1 expression in the tumor would provide a rationale for the use of immune checkpoint inhibitors for treatment of unresectable LCS

Reversible cortical lesions in primary Sjögren\u27s syndrome presenting with meningoencephalitis as an initial manifestation

金沢大学医学部附属病院放射線部We report a 50-year-old woman with primary Sjögren\u27s syndrome (SjS) who initially showed forgetfulness, and later developed disturbance of consciousness. In addition to aseptic meningoencephalitis revealed by cerebrospinal fluid examination and magnetic resonance imaging (MRI), the presence of serum anti-SS-A and anti-SS-B antibodies and inflammatory findings in lip biopsy indicated primary SjS. Fluid attenuated inversion recovery (FLAIR) of MRI revealed well defined small, high signal intensity areas in the cortex involving the subcortical white matter. Corticosteroid therapy resulted in rapid and nearly complete resolution of the cortical lesions with marked improvement of the clinical manifestations. Memory disturbance is a rare initial manifestation in meningoencephalitis associated with SjS. Our patient with SjS showed inflammatory cortical lesions on MRI, which were reversed by corticosteroid therapy. © 2005 Elsevier B.V. All rights reserved

<Abstract of Published Report>Identification of Amino Acid Residues Responsible for Difference in Substrate Specificity and Inhibitor Sensitivity Between Two Human Liver Dihydrodiol Dehydrogenase Isoenzymes by Site-directed Mutagenesis.

Human liver dihydrodiol dehydrogenase isoenzymes (DD1 and DD2), in which only seven amino acid residues are substituted, differ remarkably in specificity for steroidal substrates and inhibitor sensitivity: DD1 shows 20alpha-hydroxysteroid dehydrogenase activity and sensitivity to 1,10-phenanthroline, whereas DD2 oxidizes 3alpha-hydroxysteroids and is highly inhibited by bile acids. In the present study we performed site-directed mutagenesis of the seven residues (Thr-38, Arg-47, Leu-54, Cys-87, Val-151, Arg-170 and Gln-172) of DD1 to the corresponding residues (Val, His, Val, Ser, Met, His and Leu respectively) of DD2. Of the seven mutations, only the replacement of Leu-54 with Val produced an enzyme that had almost the same properties as DD2. No significant changes were observed in the other mutant enzymes. An additional site-directed mutagenesis of Tyr-55 of DD1 to Phe yielded an inactive protein, suggesting the catalytically important role of this residue. Thus a residue at a position before the catalytic Tyr residue might play a key role in determining the orientation of the substrates and inhibitors