Vertical antiresonant reflecting optical waveguide coupler for three-dimensional optical interconnects: optimum design for large tolerance, high coupling efficiency, and short coupling length.

A compact antiresonant-reflecting-optical-waveguide-(ARROW-) type vertical coupler for three-dimensional optical interconnects was demonstrated. The coupler consists of stacked ARROW's channeled by the stripe lateral confinement structure, and each waveguide is completely separated by a thin metal film in the separation region. In the coupling region the intermediate cladding of a previous coupler was made of the same material as that of the first cladding or the core. However, we had to overcome the problem that both the high coupling efficiency and the large fabrication tolerance cannot be achieved simultaneously. Thus we incorporated an intermediate cladding made of a material different from that of the core and the first cladding. The refractive index and the thickness of the intermediate cladding were optimally designed to achieve large fabrication tolerance and a short coupling length with a high coupling efficiency. The coupling length was reduced from 4.1 to 0.8 mm, and a high coupling efficiency of 96% was experimentally demonstrated.

Hepatic infarction with portal thrombosis.

A case of hepatic infarction with portal thrombosis is reported. A 63-year-old woman with liver cirrhosis and esophageal varices was admitted for treatment of the esophageal varices. Endoscopic variceal ligation (EVL) and endoscopic injection sclerotherapy (EIS) were performed. Two months later, she experienced right hypochondralgia and right flank pain. Serum transaminase levels were suddenly elevated, and computed tomography scans of the liver showed multiple small nodular lesions. Her condition worsened, and she died of hepatic failure. Autopsy revealed splenic and portal vein thrombosis, multiple hepatic infarction, and evidence of chronic pancreatitis. We believe that liver cirrhosis and chronic pancreatitis were the main risk factors for the portal thrombosis, and the treatment for esophageal varices appeared to have triggered the thrombosis. The hepatic infarction was caused by the portal thrombosis.

Expression of cytoskeletal-associated protein tyrosine phosphatase PTPH1 mRNA in human hepatocellular carcinoma.

We investigated the mRNA expression of cytosolic protein tyrosine phosphatase (PTPH1), which has a homologous domain to cytoskeletal-associated proteins, in human hepatocellular carcinomas (HCCs) by using reverse transcriptase-polymerase chain reaction (RT-PCR). PTPH1 mRNA was detected in all HCC cell lines (n = 6), and HCC and adjacent noncancerous tissues (n = 8) examined, indicating that PTPH1 was expressed in HCCs and hepatocytes. There was no remarkable difference in the level expression of PTPH1 mRNA between HCC and adjacent noncancerous tissues. We also performed RT-PCR single-strand conformation polymorphism (SSCP) analysis in HCC cell lines and tissues in the C-terminal region of the catalytic domain of PTPH1. In the cHc4 cell line and a HCC tissue specimen, a shifted band was detected, although it was not found in the non-cancerous tissue of the HCC specimen. Nucleotide sequence analysis showed a common mutation from T to C at the third letter of codon 919 which did not lead to amino acid substitution. These results suggest that another mutation leading to the development of HCC could occur in some region of PTPH1 other than that investigated in this study.

Prevalence of HBV and HCV infection in Japanese patients with hepatocellular carcinoma.

The prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection was investigated in 63 Japanese patients with hepatocellular carcinoma (HCC). HBV infection was confirmed by measuring hepatitis B surface antigen and HBV-DNA in the serum, and HCV infection was confirmed by measuring antibody to HCV using a 2nd generation test and HCV-RNA in serum. Some 54.0% of the patients had HCV infection only, 27.0% had HBV infection only, and 9.5% had both HCV and HBV infection. Only 9.5% of HCC patients had neither HCV nor HBV markers. These results indicate that, in Japan, HCV and HBV infection is an important factor associated with HCC, and that the hepatitis virus may have a role in the carcinogenesis of HCC.

Expression and chromosomal assignment of PTPH1 gene encoding a cytosolic protein tyrosine phosphatase homologous to cytoskeletal-associated proteins.

We have investigated the mRNA expression of 2 human protein tyrosine phosphatases with sequence homology to cytoskeletal proteins, PTPH1 and PTPMEG. Northern-blot analysis of PTPH1 using poly (A)+ RNA from normal human colon tissue showed a low-abundance message of 4.3 kb. Reverse-transcriptase/polymerase-chain reaction (RT-PCR) was therefore used to detect it in a wide variety of cell lines including 9 colorectal, 5 gastric, 5 hepatic and 6 hematopoietic tumor cells. PTPH1 mRNA was not detected only in Colo 320 cells over-expressing c-myc mRNA, among the colorectal cancer cell lines examined. When Colo 320 cells were incubated with 5 mM sodium butyrate for 5 days, PTPH1 mRNA became detectable, concomitant with the marked decrease in the expression level of c-myc mRNA. Moreover, the chromosomal localization of PTPH1 gene was investigated by fluorescence in situ hybridization. Interestingly, PTPH1 gene was mapped to 9q31 where the gene for Gorlin syndrome, a putative tumor suppressor gene, exists.

Human endothelial cells: effect of TNF-alpha on peripheral blood mononuclear cell adhesion.

Human umbilical vein endothelial cells (HUVEC) were cultured and treated for varying periods with a range of concentrations of tumour necrosis factor-alpha (TNF-alpha). After this treatment the proportion of peripheral blood mononuclear cells (PBMC), previously depleted of plastic adherent cells, capable of binding to the endothelial cells was assessed. Few PBMC bound to HUVEC which had not been pretreated with TNF-alpha but up to 36% bound after pretreatment of the endothelial cells with TNF-alpha for 10 hr at a concentration of 10 U/ml. Phenotypic characterization of the adherent and non-adherent PBMC subpopulations revealed that natural killer (NK) cells (CD16+) and a proportion of memory helper T cells (CD4+ CD45RA-) bound to TNF-alpha pretreated HUVEC but that few naive helper T cells (CD4+ CD45RA+) showed similar binding. Cytotoxicity assays for NK activity were used to analyse functionally the adherent and non-adherent PBMC subpopulations. It was found that the cell subpopulation which did not adhere to TNF-alpha pretreated HUVEC mediated little lysis of K562 target cells. Conversely, the endothelial cell-adherent PBMC subpopulation produced active lysis supporting the phenotypic evidence that NK cells were concentrated within this subpopulation. These results suggest that TNF-alpha has a rapid and profound up-regulatory effect on the expression of adhesion molecules on the surface of HUVEC. Furthermore, it is apparent that these up-regulated adhesion molecules preferentially bind NK cells and a subset of memory helper T cells from the PBMC population.

Synthesis and assignment of novel [125I]-labeled 1 alpha,25-dihydroxyvitamin D3 derivatives.

This paper describes the synthesis and structural assignment of noval 125I-1 alpha,25-dihydroxyvitamin D3 derivatives (1a) and (1b) labeled with 125I-Bolton-Hunter reagent [N-succinimidyl 3-(4-hydroxy-3-iodo[125I]phenyl)propionate] (1), which is known as a protein-labeling reagent, as tracers for radioimmunoassay (RIA). The radiospecific activities of these tracers (1a) and (1b) were calculated as 2,200 Ci/mmol (81.4 TBq/mmol).

Renal allograft rejection: investigation of alloantigen presentation by cultured human renal epithelial cells.

Defined lines of primary human renal epithelial cells were established and their expression of class II major histocompatibility (MHC) antigens was up-regulated by culture with interferon-gamma (IFN-gamma). The ability of these cells to stimulate the proliferation of allogeneic peripheral blood mononuclear cells (PBMC) was compared with that of endothelial cells and splenic mononuclear cells. It was found that both endothelial and splenic cells stimulated lympho-proliferation but that cultured renal epithelial cells were non-stimulatory. The failure of proliferation by allogeneic lymphocytes in culture with epithelial cells was not overcome by treatment with interleukin-1 (IL-1) or indomethacin. However, addition of IL-2 to mixed cultures of allogeneic PBMC and renal epithelial cells stimulated lympho-proliferation and allowed the generation of lymphoid cell lines which mediated non-specific lysis of renal epithelial cell lines. Stimulation of PBMC by mixed lymphocyte culture yielded an allospecific T-cell line which was added either to renal epithelial cells from the same donor as the stimulator cells used in the priming reaction or from a third-party donor; lympho-proliferation was observed in the specific secondary reaction but not in the non-specific reaction. These findings indicate that class II MHC antigen-expressing epithelial cells within a renal allograft may not initially stimulate the proliferation of resting allospecific recipient lymphocytes. However, within a rejecting graft it is likely that high local concentrations of IL-2 are present and that many of the infiltrating allospecific lymphocytes will be primed by previous contact with donor antigen-presenting cells, such as vascular endothelial cells or dendritic cells. Therefore, expression of class II MHC antigens by epithelial cells within the microenvironment of a renal allograft may render such cells immunogenic and able to play a direct role in the lymphocyte-mediated intragraft rejection process.

Synthesis and characterization of oligodeoxynucleotides containing the mutagenic base analogue 4-O-ethylthymine.

A method for the preparation of oligonucleotides containing the mutagenic base 4-O-ethylthymine is described for the first time. Use of p-nitrophenylethyl type base protecting groups together with phosphitetriester solid-phase methodology makes possible the rapid and efficient preparation of oligonucleotides bearing 4-O-ethylthymine, while standard base protecting groups are not compatible with the presence of this base. Possible applications of this methodology are discussed.

Membrane elasticity of mouse dorsal root ganglion neurons decreases with aging.

Elastic area compressibility modulus (EACM) method was applied to measure the membrane elasticity of cultured dorsal root ganglion neurons from fetal and 3-month-old mice. The values of the EACM were 21.3 dyn/cm in 3-month-old neurons and 2.8 dyn/cm in fetal neurons. These results indicate that neural cell membrane elasticity decreases with aging.

[The effect of ammonium fluoride solution at various concentrations on enamel].

The fluoride concentrations of ammonium fluoride solution (NH4F,pH 4.4), which has the same effect on enamel powder as conventional APF solution, were studied. Human enamel powder (200 mesh passed) was treated with solutions of NH4F (1,000 ppmF-, 3,000 ppmF-, 5,000 ppmF-, 7,000 ppmF-, 9,000 ppmF-, pH 4.4) and APF (9,000 ppmF-, pH 3.4) for 5 min. at 37 degrees C. Some of the specimen was washed with 1MKOH solution for 48 hours. Fluoride uptake by enamel powder was analyzed by means of chemical analysis and reaction products identified using X-ray diffractometry. The fluoride uptake of 5,000 ppmF- of NH4F-treated enamel was the same as that of APF-treated enamel. X-ray diffractometry showed that CaF2 was formed in the experimental groups. CaF2 with high crystallinity was formed in the NH4F-treated enamel, and the peak height of X-ray diffraction pattern of CaF2 in 3,000 ppmF- of NH4F-treated enamel was the same as that of APF-treated enamel. In conclusion, the ammonium fluoride solution of 3,000-5,000 ppmF- had a similar effect on enamel powder as conventional APF solution.

An autopsy case of intramedullary venous malformation of the spinal cord with spreading hematomyelia.

A 23-year-old Japanese woman experienced sudden severe shoulder pain, and subsequently died of cardiorespiratory arrest after an 8-day course of illness. Autopsy revealed a venous malformation in the spinal cord at the C6 level with fresh massive hemorrhage showing widespread rostrocaudal extension. The upper limit of the hemorrhage was in the left gracile nucleus of the medulla oblongata, and the lower limit was in the left posterior horn of the spinal cord at L4. The hemorrhage extended through the spinal cord, involving the left posterior horn and intermediate zone of the gray matter and the ventral part of the posterior funiculus. The mechanism of the extension of the hemorrhage and the pathogenesis of the spinal venous malformation are discussed.

Endoscopic laser coagulation through an optical laser balloon.

An endoscope was equipped with a saline-filled latex rubber balloon at its tip to displace contaminating blood, bile, or gastric contents during operative portoscopy, biliary endoscopy, or upper gastrointestinal endoscopy. A fiber with its tip inside the balloon transmitted energy from an Nd:YAG laser for coagulation of tumors in one bile duct cancer, in six portal vein growths from primary liver cancers, and in a superficially growing stomach cancer. The balloon increased the precision of irradiation by making lesions easier to identify through displacement of bile or blood and by keeping the fiber tip at a fixed position relative to the lesion. The technique, basic experimental studies, and clinical experiences are reported.

Immunocytochemical identification of beta-protein precursor in cultured vascular cells.

The immunocytochemical and immunochemical identification of beta-protein precursor in cultured vascular cells was undertaken using three types of antibodies to the synthetic predictive peptides (extracellular portion; 275-286, beta-protein portion; 597-620, C-terminal portion; 681-695) of beta-protein precursor. Monoclonal antibody directed toward the beta-protein portion stained the surface membrane of the cultured endothelial cells as well as cytoplasmic organelles. Immunoblotting of the subcellular fractions of the cell homogenate with three antibodies revealed that the plasma membrane associated beta-protein precursor consists of 105-130 kDa protein complexes and that the mitochondria-microsome-associated beta-protein consists of related 30-67 kDa protein complexes. The immunoreactivity of the protein bands was blocked by pretreating the monoclonal antibody with bovine serum albumin-conjugated beta-protein. These results indicate that the form of the beta-protein precursor or beta-protein-related components in cultured vascular cells is heterogeneous in terms of molecular size and subcellular localization.

Interactions of water-soluble porphyrins with hexadeoxyribonucleotides: resonance raman, UV-visible and 1H NMR studies.

The interactions of the water-soluble porphyrins M(TMpy-P4) [M = H2, Cu(II), Ni(II), and Co(III); TMpy-P4 = tetrakis(4-N-methylpyridyl)porphyrinato ion], with the hexadeoxyribonucleotides d(CGTACG)2, d(TACGTA)2, d(GCATGC)2, d(TGTGCA)2, and d(CTATAG)2 have been investigated by resonance Raman and/or UV-visible spectroscopy. The results indicate that all hexamers containing the 5'CG3' as well as the 5'GC3' site, and also the mismatched hexamer d(TGTGCA)2, are capable of intercalating the H2, Cu(II) and Ni(II) porphyrins. 1H nuclear magnetic resonance spectra of d(CGTACG)2 mixed with Cu(TMpy-P4) have provided further evidence for the intercalation. For the other cases, outside binding by localized electrostatic interaction is suggested. There is no evidence of groove binding to any of the hexamers. Possible reasons for different binding properties of long and short helices are discussed.

Conformation and dynamics of Z-DNA oligomer duplex of d[(CG)3TATA(CG)3] in solution.

The conformation and dynamics of a DNA oligomer, d[(CG)3TATA(CG)3], in 4M NaClO4 (Z-TATA 16 mer) have been studied by 1H NMR. The principal results of our investigation are: (i) at low temperature d[(CG)3TATA(CG)3] exists as duplexes in both low (0.1M NaCl) and high (4M NaClO4) ionic strength solutions; (ii) CGCGCG segments undergo the B-to-Z transition in 4M NaClO4; (iii) even in 4M NaClO4 the TATA box exhibits non-Z-structures and possesses multiple conformations which are slowly exchanging on the NMR chemical shift difference time scale; and, (iv) the Z-type structure of the CGCGCG segments induced in 4M NaClO4 is more conformationally mobile than its B-type counterpart in 0.1M NaCl on the nanosecond time scale.

Conformation and dynamics of a left-handed Z-DNA hairpin: studies of d(CGCGCGTTTTCGCGCG) in solution.

The physical properties of the DNA oligomer d(CGCGCGTTTTCGCGCG) in solvents containing 4 M NaClO4 and 0.1 M NaCl were investigated by proton NMR, optical melting, and circular dichroism spectroscopy. Results of these investigations are as follows: (i) The DNA hexadecamer exists as a unimolecular hairpin in either high or low salt. (ii) In high salt the stem region of the hairpin is in the left-handed Z conformation. (iii) In either high or low salt, the duplex stem of the hairpin is stabilized against melting by approximately 40 degrees C compared to the linear core duplex. The added stability of the hairpin is entropic in origin. (iv) In high salt, as the temperature is elevated, the equilibrium structure of the duplex stem of the hairpin shifts from the Z to the B conformation before melting. (v) In low salt, when the DNA duplex exists in the B conformation, attachment of a T4 single-strand loop to one end only slightly decreases (by 14%) the correlation time of the CH5-CH6 interproton vector. In high salt, when the DNA duplex exists in the Z conformation, the correlation time of the CH5-CH6 interproton vector decreases by 51%. Since these viscosity-corrected correlation times are taken to be indicators of duplex motions on the nanosecond time scale, this result directly suggests a larger amplitude of these motions is present in the duplex stem of the hairpin when it exists in the Z conformation.

Adaptation of cultured mammalian neurons to a hypotonic environment with age-related response.

The response of neurons to osmolal concentration changes has not been well-documented compared to erythrocytes, urinary bladder and epithelial cells. The effects of a hypotonic solution on morphology and electrophysiological functions in cultured dissociated neurons can be precisely studied. From the analysis of video pictures from Nomarski optics, diameters of the cells were seen to increase and then recover to the initial values after the application of a hypotonic solution. The rate of increase of cell size in fetal neurons was 4-5 times faster than in mature neurons. This age-related transient response was accompanied by a change of resting potential and membrane resistance. This transient depolarization and decrease of the resistance corresponded to morphological changes. However, the amplitude of an action potential scarcely changed during the cell membrane expansion. It is plausible that increased membrane tension caused by the membrane expansion might facilitate the opening of the channel. The cell membrane expansion might also increase ionic permeability through the membrane. This may reduce a swollen cell volume to the initial one by diluting their intracellular solute concentration. After this adaptation the cultured neurons were able to survive for a long time and extend processes in the hypotonic environment.

X-ray structure of a DNA hairpin molecule.

We have solved the crystal structure of a synthetic DNA hexadecanucleotide of sequence: C-G-C-G-C-G-T-T-T-T-C-G-C-G-C-G, at 2.1 A resolution, and observed that it adopts a monomeric hairpin configuration with a Z-DNA hexamer stem. In the T4 loop the bases stack with one another and with neighbouring molecules of the crystal, and not with base pairs of their own hexamer stem. Two thymine T10 rings from different molecules stack between the C1-G16 ends of a third and a fourth hairpin helix, in a manner that suggests T-T base 'pairing' and simulates a long, 13-base-pair helix. Although such T-T interactions would not be present in solution, they illustrate a remarkable tendency of thymines for self-association. Purine-purine G-A base pairs are known to exist in the anti-anti conformation with an increase in local helix width; it may be that more serious consideration should be given to the possible existence of pyrimidine-pyrimidine C-T base pairs with decreased local helix width, particularly where several such base pairs occur sequentially.