New methods for measuring atlanto-axial vertical subluxation in rheumatoid arthritis by MR imaging]

This communication describes one pediatric neurosurgeon's personal view of the neurosurgical perspectives in pediatric neurooncology. Various roles of surgery, including histological verification, maximum cytoreduction, neurodecompression and restoration of the cerebrospinal fluid pathway, are emphasized. A pediatric neurosurgeon, who is the first person to make decisions on diagnosis and treatment relating to children with brain tumors, should be up to date with advances in diagnostic and therapeutic methods. Particularly, he or she should be familiar with both the efficacy and the side effects of radiation therapy and chemotherapy to allow selection of the optimum treatment for such children.     

InP/InGaAs double-heterojunction bipolar transistor with step-graded InGaAsP collector

An MOCVD-grown InP/InGaAs double-heterojunction bipolar transistor with a step-graded InGaAsP collector is described. This transistor allows high injection current densities over 2.9*10/sup 5/ A/cm/sup 2/, which suggests no significant current blocking related to the wide-gap InP layers. A cutoff frequency of 155 GHz and a maximum oscillation frequency of 90 GHz are obtained at the collector current density of 1.6*10/sup 5/ A/cm/sup 2/.<>     

Involvement of heat shock protein 90 in the degradation of mutant insulin receptors by the proteasome

We previously reported three families with type A insulin-resistant syndrome who had mutations, either Asp1179 or Leu1193, in the kinase domain of the insulin receptor. The extreme insulin resistance of these patients was found to be caused by the decreased number of insulin receptors on the cell surface, due to the intracellular rapid degradation (Imamura, T., Takata, Y., Sasaoka, T., Takada, Y., Morioka, H., Haruta, T., Sawa, T., Iwanishi, M., Yang, G. H., Suzuki, Y., Hamada, J., and Kobayashi, M. (1994) J. Biol. Chem. 269, 31019-31027). In the present study, we first examined whether these mutations caused rapid degradation of unprocessed proreceptors, using the exon 13 deleted mutant insulin receptors (DeltaEx13-IR), which were accumulated in the endoplasmic reticulum as unprocessed proreceptors. The addition of Asp1179 or Leu1193 mutation to DeltaEx13-IR caused accelerated degradation of the unprocessed DeltaEx13-IR in the transfected COS-7 cells. Next, we tested whether these mutant receptors were degraded by the proteasome. Treatment with proteasome inhibitors Z-Leu-Leu-Nva-H (MG-115) or Z-Leu-Leu-Leu-H (MG-132) prevented the accelerated degradation of these mutant receptors, resulting in increased amounts of the mutant receptors in the COS-7 cells. Essentially the same results were obtained in the patient's transformed lymphocytes. Finally, we found that these mutant receptors bound to heat shock protein 90 (Hsp90). To determine whether Hsp90 played an important role in the accelerated receptor degradation, we examined the effect of anti-Hsp90 antibody on the mutant receptor degradation. The microinjection of anti-Hsp90 antibody into cells prevented the accelerated degradation of both Asp1179 and Leu1193 mutant insulin receptors. Taken together, these results suggest that Hsp90 is involved in dislocation of the mutant insulin receptors out of the endoplasmic reticulum into the cytosol, where the mutant receptors are degraded by the proteasome.     

Low-complexity bit-interleaved coded DAPSK for Rayleigh-fading channels

We analyze the achievable performance of bit-interleaved coded differential amplitude and phase-shift keying (DAPSK) systems over frequency nonselective Rayleigh-fading channels with suboptimal differential detection assuming an ideal bit interleaving. The suboptimal differential detection in this work refers to the bit metric calculation based only on the difference between two consecutive symbols, in contrast to more complex maximum-likelihood (ML)-based differential detection, which makes use of all the observed consecutive symbols for its metric calculation in channel decoding. As benchmarks of coded system performance, we analyze the average mutual information (AMI) and cutoff rate of this system. Exact probability density functions of the suboptimal differential detector outputs are derived for this purpose. Comparative studies suggest that the performance loss of the suboptimal approach is in fact noticeable. Therefore, we also develop a low-complexity receiver structure in the framework of suboptimal differential detection that can approach the performance of ML-based system by suitably incorporating the amplitude statistics of received symbols. The theoretical framework developed in this paper is also confirmed by simulations using convolutional and turbo codes.     

Apolipoprotein E polymorphism is associated with plasma cholesterol response in a 7-day hospitalization study for metabolic and dietary control in NIDDM

An 81-year-old woman in whom liver dysfunction had been pointed out 3 years previously was diagnosed as having liver cirrhosis due to lupoid hepatitis. Considering the poor prognosis of cirrhosis and her age, immunosuppressive therapy was not adopted. Nine months later, a small liver tumor was found by ultrasonography and was diagnosed as hepatocellular carcinoma (HCC). The tumor was treated with transcatheter arterial embolization, but grew continuously. She also developed gingival lymphoma that was successfully treated. Three years after initial diagnosis of lupoid hepatitis, she died of hepatic failure. An autopsy was performed and confirmed the clinical diagnosis, liver cirrhosis with HCC. HCC is regarded as a rare complication of lupoid hepatitis, but cases of HCC complicating lupoid hepatitis may increase with progress in treatment methods and elongation of survival. The present case suggests that any malignancy can be developed in long-term surviving patients with lupoid hepatitis.     

Unbiased InP detectors in the submillimetre wave region

High sensitivity unbiased detectors employing Ni-nInP Schottky-barrier diodes have been developed in a submillimetre-wave region. The voltage sensitivities of 120 V/W at 300 GHz and 17 V/W at 450 GHz were obtained, which are about three times higher than those of the usually used unbiased Si point contact diode detectors.     

MnGeP<Subscript>2</Subscript> Thin Films Grown by Molecular Beam Epitaxy

Growth conditions for MnGeP₂ thin films have been investigated by using molecular beam epitaxy (MBE) method. Mn and Ge were evaporated by K-cells, and P₂ was supplied by decomposing tertialybutylphosphine (TBP). GaAs (001) and InP (001) single crystals were used as substrates. An X-ray diffraction peak, which can be assigned to (008) peak of MnGeP₂, was observed at nearly the same position as the (004) peak of GaAs. The lattice constant of the MnGeP₂ thin film was determined to be 1.13 nm assuming its crystal structure is a c-axis oriented chalcopyrite type structure. Secondary phases such as GeP, MnGe _x and MnP were observed for beam fluxes of Mn and Ge as high as 1×10^?8 Torr.     

Phase transitions in R2 SnCl6-type crystals (R = NH3 C2H3, NH3C2H5 and N(CH3)4)

The thermal dilatation in (NH₃ ·CH₃) SnCl₆, (NH₃ · C₂H₅) SnCl₆ and [N(CH₃)] SnCl₆ was measured, and as the results it has turned out that (NH₃ ⁶·C₂H₅) SnCl₆ and [N(CH₃)₄]₂ SnCl₆ undergo the first order transitions at 128 K and 158 K, respectively. The low temperature phases of (NH · C₂H₅) SnCl₆ and [N(CH₃)₄]₂ SnC1₆ are found to be monoclinic and tetragonal, respectively, No phase transition was observed in (NH₃ ·CH₃)₂ SnCl₆ down to 77 K.