Ontogeny of the murine Ig joining chain gene and protein

We used Northern blot analysis in order to investigate the ontogeny of the murine joining (J)-chain gene. No J-chain expression was detected in embryonic tissues, including liver, spleen and intestine, but an expression of mu heavy chain was detected in foetal liver at day 17. J-chain expression was detected in the spleen at day 9 and in the intestine at day 15 after birth. Western blot analysis was carried out in order to compare the protein levels of J and mu heavy chains in serum from day 8 to day 24 after birth, using antihuman J chain and antimouse mu chain antibodies. Although mu chain protein could be detected in serum from day 8, J-chain protein was detectable only at day 24. These results suggest that the expression of J chain is a later event than the mu chain in the mouse, which thus differs in embryogenesis from humans.     

T-cell-specific expression of kinase-defective Eph-family receptor protein, EphB6 in normal as well as transformed hematopoietic cells

Although most kinase-defective growth factor receptor proteins are associated with pathogenic conditions, a kinase-defective Eph-family receptor protein, EphB6, is expressed in normal human tissues. We generated monoclonal antibodies specific for human EphB6 to characterize its expression on human hematopoietic cells. A very small population of normal human peripheral white blood cells (0.57 +/- 0.07%, n = 12) expressed EphB6. The EphB6-positive cells were CD2+, CD7+, CD3+ and CD4+ or CD8+ lymphocytes, but they did not express CD19 or CD11b. In human bone marrow, only 1.5 +/- 0.19% of lymphocytes expressed EphB6. Compared with the expression in peripheral lymphocytes, prominent expression of EphB6 protein was demonstrated in CD4+CD8+ double-positive mouse thymocytes. The T-cell lineage-specific expression was strictly conserved in human leukemia/lymphoma cells. Among T-cell-derived leukemia cells, the expression level of EphB6 seemed to decrease with maturation of the cells. These results suggest that EphB6 expression is regulated in T-cell development.     

Clinical significance of IgG4 antibody determination in children against egg white, milk, soybean and Dermatophagoides farinae]

The measurement of IgE and IgG4 antibodies against egg white, milk, soybean and Dermatophagoides farinae was performed by FAST (fluorescence allergosorbent test) using 21 serum samples obtained from non-allergic children and 160 serum samples from atopic children with bronchial asthma and/or atopic dermatitis. Their antibody levels were evaluated for any association with disease severity and for clinical significance in establishing diagnosis. It was found that children with bronchial asthma showed lower levels of IgE antibodies against egg white, milk and soybean and higher levels of IgE antibodies against Dermatophagoides farinae compared with those of children with atopic dermatitis, while both groups showed higher levels of egg white and milk-specific IgG4 antibodies compared with non-allergic children. These IgE and IgG4 antibody levels revealed a tendency to correlate with disease severity in patients with atopic dermatitis, while this was not observed in patients with bronchial asthma. The contribution percentages of IgG4 antibody determination, together with IgE antibody determination, in retrieving causal allergens were 71% for egg white, 70% for milk and 48% for soybean allergy, implying their diagnostic value in establishing clinical diagnosis.     

Two-dimensional dosimetry in the near field of the model 200 103Pd source for interstitial brachytherapy implants using a thermoluminescent sheet

A large area and highly sensitive thermoluminescent (TL) sheet film was used for two-dimensional dose distribution measurements at millimetre distances from a 103Pd interstitial brachytherapy source. The TL film is made of Teflon homogeneously mixed with small particles of thermoluminescent material (BaSO4: Eu doped). This TL sheet (5 cm x 5 cm) was used to determine the relative dosimetric characteristics (i.e., radial dose function, 2D and 1D anisotropy functions, as defined by the updated AAPM Task Group No 43 report) of the model 200 103Pd source that emits low energy photons (21 keV). The two-dimensional dosimetry data were obtained for distances from the source surface to 15 mm. The radial dose function measured with the TL sheet is in reasonable agreement within 11% with the values recommended in the updated AAPM TG-43 report. All the measured 2D dose distributions showed limited symmetry about the source axes. The differences between the 1D anisotropy function values measured with the TL sheet and the data recommended in the updated AAPM TG-43 report were 10% at 5 mm and 7.5% at 10 mm, respectively, for the model 200 103Pd seed. Our experiments have demonstrated that it is feasible to use the TL sheet as a dosimeter in the determination of the dosimetric characteristics in the immediate vicinity of interstitial brachytherapy sources emitting low energy photons.     

Crystal Growth in Poly(L‐lactide) Thin Film Revealed by in situ Atomic Force Microscopy

Direct visualization of crystal growth in poly(L ‐lactide) thin films was carried out by using a temperature‐controlled atomic force microscopy (AFM). At the initial stage of crystallization, edge‐on lamellar crystals have nucleated and elongated. Subsequently, the edge‐on lamellar crystals showed S‐shaped morphology and changed their orientation from edge‐on manner to flat‐on one. The curvature of edge‐on lamellar crystal has been discussed in terms of inclination and distortion of polymer chains in the crystal. In addition, mechanism on the formation of flat‐on crystal from edge‐on lamellae was proposed as derivative growth on the basis of in situ AFM observation of crystal growth and enzymatic degradation.

     

Effect of phospholipase A2 inhibitors on mouse T lymphocytes. I. Phospholipase A2 inhibitors exert similar immunological activities as glycosylation inhibiting factor

Since our previous experiments suggested that glycosylation-inhibiting factor (GIF) is a phosphorylated derivative of a phospholipase inhibitory protein, we determined whether other well-known phospholipase inhibitors may have similar biological activities. The results showed that phospholipase A2 (PLA2) inhibitors, such as recombinant human lipocortin I and ONO-RS-082, could switch T cell hybridoma 12H5 cells from the formation of glycosylated IgE-binding factors (IgE-BF) to the formation of unglycosylated IgE-BF, whereas neomycin, a phospholipase C inhibitor, failed to affect the nature of IgE-BF formed by the cells. The minimum concentrations of lipocortin I and ONO-RS-082 required for switching the 12H5 cells to the formation of unglycosylated IgE-BF were comparable to or less than IC50 of the inhibitors for PLA2. The ability of partially purified GIF to switch the 12H5 cells to the formation of unglycosylated IgE-BF was markedly enhanced by treatment of the preparation with alkaline phosphatase. It was also found that lipocortin I and ONO-RS-082, but not neomycin, facilitated the generation of GIF-producing T cells. When spleen cells of ovalbumin (OVA)-primed BDF1 mice were stimulated with homologous antigen and the activated T cells were propagated by recombinant IL-2 in the presence of GIF, lipocortin I, or ONO-RS-082, T cells obtained in the cultures constitutively produced their own GIF. Antigenic stimulation of the T cells induced the formation of unglycosylated IgE-BF and GIF with an affinity for OVA.(ABSTRACT TRUNCATED AT 250 WORDS)     

Long-term accumulation of amyloid-beta, beta-secretase, presenilin-1, and caspase-3 in damaged axons following brain trauma

Plaques composed of amyloid beta (Abeta) have been found within days following brain trauma in humans, similar to the hallmark plaque pathology of Alzheimer's disease (AD). Here, we evaluated the potential source of this Abeta and long-term mechanisms that could lead to its production. Inertial brain injury was induced in pigs via head rotational acceleration of 110 degrees over 20 ms in the coronal plane. Animals were euthanized at 3 hours, 3 days, 7 days, and 6 months post-injury. Immunohistochemistry and Western blot analyses of the brains were performed using antibodies specific for amyloid precursor protein (APP), Abeta peptides, beta-site APP-cleaving enzyme (BACE), presenilin-1 (PS-1), caspase-3, and caspase-mediated cleavage of APP (CCA). Substantial co-accumulation for all of these factors was found in swollen axons at all time points up to 6 months following injury. Western blot analysis of injured brains confirmed a substantial increase in the protein levels of these factors, particularly in the white matter. These data suggest that impaired axonal transport due to trauma induces long-term pathological co-accumulation of APP with BACE, PS-1, and activated caspase. The abnormal concentration of these factors may lead to APP proteolysis and Abeta formation within the axonal membrane compartment.     

Non-adhesive cyanoacrylate as an embolic material for endovascular neurosurgery

Endovascular neurosurgery is now becoming available as one of strategies for the treatment of cerebro-spinal arterio-venous malformations and aneurysms. For this treatment, a microcatheter is advanced into or close to a lesion and then an embolic material is administered through it to obliterate the lesion. N-butyl-2-cyanoacrylate (NBCA) has preferentially been used as an embolic material in Europe and America. However, its exceptionally strong adhesive force sometimes causes adhesion between the tip of the microcatheter and the artery. In this study, a new non-adhesive cyanoacrylate, isostearyl-2-cyanoacrylate (ISCA), was developed. It carries a long hydrophobic side isostearyl group with lower reactivity and adhesion than other cyanoacrylates. Its polymerization rate is, however, too low to obliterate a vascular lesion with a rapid blood flow. To increase the polymerization rate. ISCA was mixed with NBCA. As a result, the adhesive force of the mixture became extremely low, compared with that of NBCA. The viscosity of the mixture was low enough to allow its' use as an embolic material. Tissue reactions against the mixture was milder than those against NBCA. Radio-angiography became possible by mixing further with Lipiodol. The evaluation of this new embolic material with a rabbit renal artery showed that the obliteration effect of the mixture of ISCA and NBCA was excellent to use as an embolic material for clinical applications.     

Evolutionary relationships among the gnat-transmitted orbiviruses that cause African horse sickness, bluetongue, and epizootic hemorrhagic disease as evidenced by their capsid protein sequences.

The amino acid sequences of four major capsid proteins of African horse sickness virus (serotype 4, AHSV-4) have been compared with those of Bluetongue virus of sheep. Epizootic hemorrhagic disease virus of deer, and the phylogenetic relationships established. Complete nucleotide sequence analysis of three RNA segments (L2, L3, and M6) of AHSV-4 and their encoded products, VP2, VP3, and VP5, together with previously published data for VP7 (Roy et al., 1991), have revealed that of the four capsid proteins the innermost protein, VP3, is the most conserved, and the outermost protein, VP2, is the most variable. Some 57-58% of the aligned BTV-10 and EHDV-1 VP3 amino acids are identical with those of AHSV-4. This compares to an identity of 79% between the BTV and EHDV VP3 sequences. For the VP7 proteins 64% of the aligned amino acids are identical between BTV-10 and EHDV-1, while they share 44-46% amino acid residues with the aligned VP7 protein of AHSV-4. By contrast, the VP2 proteins of the three viruses share only 19-24% identical amino acids. Various other comparative analyses of the proteins indicate that the VP2 species of the three orbiviruses are similar. Unlike VP2, the other outer capsid protein, VP5 is more conserved among the three viruses. On alignment, the VP5 of AHSV-4 has some 43-45% identical amino acids with that of BTV-10 and EHDV-1. Between BTV and EHDV, 62% of the aligned sequences are identical.