[Amyloidosis secondary to bronchiectasis]

A 77-year-old woman was hospitalized repeatly due to frequent hemoptysis and production of bloodly sputum for several years. Bronchography in 1989 revealed bronchiectasis. She had complained of abdominal pain and diarrhea since 1991, and her urine was first positive for protein in 1992. She was admitted to our hospital in October 1992 because of edema, anemia, and hypoproteinemia. Despite treatment, renal dysfunction and the gastrointestinal disorder progressed and she died in January 1993. An autopsy revealed diffuse depositions of amyloid in many organs, especially in the kidney and the gastrointestinal tract. This amyloid protein was identified as AA protein, which was suggestive of secondary amyloidosis. Bronchiectasis appears to have been the disease underlying this patient's amyloidosis.

The POU domain transcription factor Brn-2 is required for the determination of specific neuronal lineages in the hypothalamus of the mouse

We generated mice carrying a loss-of-function mutation in Brn-2, a gene encoding a nervous system specific POU transcription factor, by gene targeting in embryonic stem cells. In homozygous mutant embryos, migratory precursor cells for neurons of the paraventricular nuclei (PVN) and the supraoptic nuclei (SO) of the hypothalamus die at approximately E12.5. All homozygous mutants suffered mortality within 10 days after birth, possibly because of a complete deficiency of these neurons in the hypothalamus. Although neither developmental nor histological abnormalities were observed in heterozygous mice, the levels of expression of vasopressin and oxytocin in the hypothalamus of these animals were half these of wild-type mice. These results strongly suggest that Brn-2 plays an essential role in the determination and development of the PVN and SO neuronal lineages in the hypothalamus.

Characterization of a specific monoclonal antibody 9F5-3a and the development of assay system for oxidized HDL

We obtained a monoclonal antibody 9F5-3a against oxidative low-density lipoprotein (LDL) modified with CuSO4 and established a sandwich ELISA for detection of oxidized high-density lipoprotein (oxHDL). The 9F5-3a was reacted strongly with oxHDL and to a lesser degree with oxLDL and LDL. In contrast, little or no reactivity was found with HDL. When the generation of oxHDL was limited by the addition of alpha-tocopherol and catalase, reactivity to 9F5-3a was reduced. Incubation of oxHDL with excess lyso-phosphatidylcholine (lyso-PC) also reduced immunoreactivity, but not by only lyso-PC. These results suggested that the epitope is possibly associated with oxHDL-linked lyso-PC induced mainly by the hydroxyl radical.

Sea urchin egg tropomyosin isoforms with muscle-type and nonmuscle-type antigenicities

Egg tropomyosins were prepared from four sea urchin species, Stronglyocentrotus intermedius, Anthocidaris crassispina, Hemicentrotus pulcherrimus and Pseudocentrotus depressus, and their molecular heterogeneity was investigated by electrophoresis and immunoblotting. The molecular heterogeneity of egg tropomyosins was species-specific, and two to four kinds of tropomyosin isoforms were detected, the apparent molecular weights of which were 29,000-32,000. The egg tropomyosin isoforms could be classified into two groups with muscle- and nonmuscle-type antigenicities in each species. No obvious difference in their cytological localization was observed immunocytochemically in S. intermedius and H. pulcherrimus.

Neurite outgrowth of murine cerebellar granule cells can be enhanced by aniracetam with or without alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)

To assess the neurotrophic effects of a nootropic drug, aniracetam, we studied neurite extension of mouse cerebellar granule cells in culture with low or with high K+ under different combinations of drugs and then immunohistochemically stained the cells with an antibody against L1, a neural cell adhesion molecule on cerebellar granule cells. Quantitative analyses using parameters of the total neurite length, maximal neurite length and number of branches disclosed that aniracetam, in the presence of high K+ and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA), significantly enhanced neurite extension of cultured granule neurons. Aniracetam alone also stimulated neurite extension of cerebellar granule cells at a longer period of culture with low K+ showing a bell-shaped dose response curve with maximal effects at 10 microM. Aniracetam may influence remodeling of the neural network after injury.

M-wave modulation at relative levels of maximal voluntary contraction

Frequency (mean and median power frequency, f and fm) and amplitude (average rectified and root mean square values, ARV and rms), parameters of the M-wave, and the dorsiflexor force parameters of the anterior tibial muscles were measured in seven healthy human subjects. Intermittent, voluntary contractions at relative intensities (40%, 60%, and 80%) of maximal voluntary contraction (MVC) were performed in conjunction with electrical stimulation. The M-wave parameter changes were measured over the course of the isometric contractions. At higher force levels, M-wave potentiation was observed as increases in both ARV and rms. The ARV augmentation attained levels as high as 206.1 (SD 7.4)% of resting values after both initial and final contractions of 80% MVC, reaching statistical significance (P < 0.01). The f and fm failed to show a significant difference at any level of contraction. It was surmised that potentiation of the M-wave was the result of an increased contribution of muscle fibre type IIb recruited during higher contraction levels, reflecting the change to larger, deeper innervating motoneurons as the intensity of contraction, as a percentage of MVC, rose. Recruitment of type IIb fibres, which have been reported to have a higher energy potential and frequency content, were thought to reflect changes in the local excitability threshold of some motor units as the force intensity increased during the intermittent voluntary contractions. It is suggested that the M-wave elicited after contractions has the potential to reflect, to some extent, motor unit recruitment changes resulting from the preceding contractions, and that through comparisons of M-wave amplitude parameters contributions of varying fibre types over the course of a contraction may be indicated.

Dnacin A1 and dnacin B1 are antitumor antibiotics that inhibit cdc25B phosphatase activity

The p80cdc25 protein is a protein phosphatase directly involved in p34cdc2 protein kinase activation by dephosphorylation. The cdc25B gene is one of three human cdc25 homologs which can complement the temperature-sensitive cdc25 mutation of Schizosaccharomyces pombe, and is expressed a high levels in human cell lines, particularly in some cancer cells. A fusion protein of glutathione-S-transferase (GST) and the catalytic domain of cdc25B protein was constructed and found to retain phosphatase activity in the manner of a p80cdc25 phosphatase by using a chromogenic substrate, p-nitrophenylphosphate. Two benzoquinoid antitumor compounds, dnacin A1 and dnacin B1, inhibited phosphatase activity in a non-competitive manner.

Carbohydrate-mediated recognition of a circulating placental alkaline phosphatase-immunoglobulin M complex

We detected an abnormal alkaline phosphatase (AP) electrophoretically in the serum of a patient with rheumatoid arthritis, who had a macromolecular AP linked with immunoglobulin M (IgM) bearing a kappa light chain. The IgM isolated from the AP-IgM complex in the patient's serum reacted apparently with all of the AP isozymes tested, i.e. those originating in the liver, bone, intestine and placenta, but the alpha-mannosidase-treated IgM from the patient's serum bound to placental AP (PAP) alone. This suggests that untreated IgM recognizes multivalent epitopes of the AP and that the complex of AP with alpha-mannosidase-treated IgM is a specific antibody-antigen complex. In order to investigate further the multivalent binding capacity for the PAP-untreated IgM complex, we prepared a monoclonal antibody (MoAb) against PAP and identified it as an IgM with a kappa light chain. The binding affinities and their circulating half-lives of the synthetic complexes of PAP and respective MoAbs were examined with and without treatment with several glycosidases. The untreated MoAb bearing IgM had binding affinity for all of the AP isozymes tested, while alpha-mannosidase-treated IgM attached only to PAP, the same as the IgM isolated from the PAP-IgM complex in the patient's serum. The circulating clearance of the PAP-IgM complex in rabbits was faster than either component alone. In addition, the PAP-IgM complex treated with alpha-mannosidase was found to have the shortest half-life of all the complexes of PAP and Igs treated with the several glycosidases tested. These results suggest that the formation of the PAP-IgM complex as an enzyme-linked antibody and the clearance of the complex in vivo are dependent on the sugar moieties of the Igs.

Enzyme-linked immunosorbent assay for human pulmonary surfactant protein D

We developed a simple and sensitive enzyme-linked immunosorbent assay (ELISA) for human pulmonary surfactant protein D (SP-D). Human SP-D was purified from bronchoalveolar lavage fluids of patients with pulmonary alveolar proteinosis. Nine monoclonal antibodies (MAbs) were established from BALB/c mice immunized with the purified human SP-D. All MAbs were directed to either 43 kDa SP-D contained in lung lavage fluids of patients with pulmonary alveolar proteinosis or in amniotic fluids from healthy normal pregnancies. The ELISA is based on a sandwich method using two MAbs, 6B2 and 7C6. Cross-reactivity to human SP-A or rat SP-D was evaluated as below 0.6%. The recovery of different concentrations of SP-D ranged from 94.4% to 111.2%, and serial dilutions of amniotic fluids showed good linearity. SP-D concentrations in 21 amniotic fluids from normal pregnancies were measured by the ELISA. The mean concentration in amniotic fluids from pregnancies in the third trimester was significantly higher than that from earlier stages of gestation (p < 0.001), indicating that this ELISA may be applicable for prediction of fetal lung maturity.

Cdc25A is a novel phosphatase functioning early in the cell cycle

The cdc25+ tyrosine phosphatase is a key mitotic inducer of the fission yeast Schizosaccharomyces pombe, controlling the timing of the initiation of mitosis. Mammals contain at least three cdc25+ homologues called cdc25A, cdc25B and cdc25C. In this study we investigate the biological function of cdc25A. Although very potent in rescuing the S.pombe cdc25 mutant, cdc25A is less structurally related to the S.pombe enzyme. Northern and Western blotting detection reveals that unlike cdc25B, cdc25C and cdc2, cdc25A is predominantly expressed in late G1. Moreover, immunodepletion of cdc25A in rat cells by microinjection of a specific antibody effectively blocks their cell cycle progression from G1 into the S phase, as determined by laser scanning single cell cytometry. These results indicate that cdc25A is not a mitotic regulator but a novel phosphatase that plays a crucial role in the start of the cell cycle. In view of its strong ability to activate cdc2 kinase and its specific expression in late G1, cdc2-related kinases functioning early in the cell cycle may be targets for this phosphatase.

Molecular cloning of a novel Ca(2+)-binding protein (calmegin) specifically expressed during male meiotic germ cell development

During mammalian spermatogenesis, many specific molecules are expressed. We have recently identified a 93-kDa male meiotic germ cell-specific antigen (Meg 1) exclusively expressed in germ cells from the pachytene spermatocyte to the spermatid stage using the monoclonal antibody TRA 369 (Watanabe, D., Sawada, K., Koshimizu, U., Kagawa, T., and Nishimune, Y. (1992) Mol. Reprod. Dev. 33, 307-312). In this study, we cloned a cDNA representing this antigen from a mouse testis cDNA expression library, using the monoclonal antibody TRA 369. Northern blotting showed that this transcript was 2.3 kilobases in length and was expressed only in the testis and not in other somatic tissues or in the ovary. The expression of the mRNA was first detected at the pachytene spermatocyte stage of male germ cell development, and this expression was correlated with the expression of the protein. Sequence analysis of the cDNA revealed that the predicted protein consists of 611 amino acids, including a hydrophobic NH2 terminus characteristic of a signal peptide, two sets of internal repetitive sequences (four repeats of IPDPSAVKPEDWDD and GEWXPPMIPNPXYQ), and a hydrophilic COOH terminus. The deduced amino acid sequence has 58% homology with dog calnexin (the ER membrane phosphoprotein of pancreatic cells) and significant partial homology with calreticulin (high affinity Ca(2+)-binding protein of the ER membrane) at the repetitive sequence. Furthermore, we demonstrated the 45Ca2+ binding ability of this antigen by a 45Ca2+ overlay assay, and the name calmegin is proposed for this antigen. Calmegin is a novel Ca(2+)-binding protein that is specifically expressed in spermatogenesis. The highly regulated, specific, and abundant expression of calmegin suggests that it has important roles in spermatogenesis.

Participation of an arginyl residue of insulin chain B in the inhibition of hemagglutination by Porphyromonas gingivalis

Insulin chain B, containing each one arginyl and lysyl residue in its peptide chain, inhibited hemagglutination by Porphyromonas gingivalis. To determine the further inhibitory profile, chain B was digested into 4 fragments by protease, which was contained in the preparation of hemagglutinin from P. gingivalis. Identification of each fragment by the amino acid analysis revealed that the chain was cleaved at the carboxyl site of arginyl and/or lysyl residues, but one fragment contained citrulline instead of arginine at its carboxyl terminal. This citrulline might have originated from arginine by an arginine deiminase-like enzyme of P. gingivalis. Only one fragment that contained the arginyl residue exhibited inhibitory activity on hemagglutination, but it was considerably weakened compared with that of the intact chain B. The difference in the inhibitory activity seemed to depend on the position of an arginyl residue in the peptide; this was also confirmed using several derivatives of bradykinin. The present result suggests that the internal arginyl residue in a peptide chain may be critical for the inhibition of the hemagglutination by P. gingivalis.

Modification of 1 alpha,25-dihydroxyvitamin D3 metabolism by introduction of 26,26,26,27,27,27-hexafluoro atoms in human promyelocytic leukaemia (HL-60) cells: isolation and identification of a novel bioactive metabolite, 26,26,26,27,27,27-hexafluoro-1 alpha,23(S),25-trihydroxyvitamin D3

To study whether the introduction of fluoro atoms into C-26 and C-27 positions on the 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3] molecule could affect metabolism in human promyelocytic leukaemia (HL-60) cells, we compared the metabolism of 26,26,26,27,27,27-hexafluoro-1 alpha,25-dihydroxyvitamin D3 [26,27-F6-1 alpha,25(OH)2D3] and 1 alpha,25(OH)2D3 in HL-60 cells. 26,27-F6-1 alpha,25(OH)2D3 was mainly converted into a new bioactive metabolite, 26,26,26,27,27,27-hexafluoro-1 alpha,23(S),25- trihydroxyvitamin D3 [26,27-F6-1 alpha,23(S),25(OH)3D3], but not into 26,26,26,27,27,27-hexafluoro-1 alpha,24(R),25-trihydroxyvitamin D3 [26,27-F6-1 alpha,24(R),25(OH)3D3] in HL-60 cells. 26,27-F6-1 alpha,23(S),25(OH)3D3 was identified by combinations of h.p.l.c., u.v. spectroscopy and g.c.-mass spectrometry. Evidence is presented that 26,27-F6-1 alpha,25(OH)2D2 was metabolized to 26,27-F6-1 alpha,23(S),25(OH)3D3 by C-23 hydroxylation as a first step of the metabolism, and the 23-hydroxylated bioactive metabolite was accumulated in the cells, whereas 1 alpha,25(OH)2D3 was initially deactivated and metabolized to 1 alpha,24(R),25(OH)3D3 by C-24 hydroxylation through a side-chain oxidation pathway resulting in C23-C24 cleavage, yielding 24,25,26,27-tetranor-1 alpha,23(OH)2D3 in HL-60 cells. These results show that 26,27-F6-1 alpha,25(OH)2D3 and 1 alpha,25(OH)2D3 are metabolized by different metabolic pathways in HL-60 cells.

Cytotoxicity of Porphyromonas gingivalis toward cultured human gingival fibroblasts

Direct cytotoxicity of black-pigmented anaerobic rods was studied on the confluent monolayer of human gingival fibroblasts in vitro. Only strains of Porphyromonas gingivalis caused morphological alteration (cell-rounding) and notable depression of viability of fibroblasts. To determine the location of the cytotoxicity, bacterial surface components, i.e., outer membrane, lipopolysaccharide, fimbriae and outer membrane vesicles were prepared from P. gingivalis and their cytotoxicity was assessed. Among these preparations, only outer membrane vesicles are supposed to have high affinity to human gingival fibroblasts, and the cytotoxicity of outer membrane vesicles was found to be much stronger than that of the other constituents. This cytotoxic factor seemed to consist largely of protein and to be associated with the enzyme activity of outer membrane vesicles. The effects of some protease inhibitors and L-cysteine on the cytotoxicity of outer membrane vesicles suggest that the mechanism of cell-rounding is different from that of cell death.

Cyclin G: a new mammalian cyclin with homology to fission yeast Cig1

A new gene encoding a cyclin-like protein has been isolated from a rat fibroblast cDNA library by cross-hybridization with a mixture of c-src family proto-oncogene kinase domains as a probe. This putative cyclin, called cyclin G, contains a typical cyclin box at the N-terminus but no apparent 'destruction box' or 'PEST' sequence. Interestingly, in its C-terminus region, it has a sequence homologous with a tyrosine phosphorylation site of the epidermal growth factor receptor. Although this cyclin is phylogenetically related to HCS26 of Saccharomyces cerevisiae, it most resembles Cig1, a B-type cyclin, of Schizosaccharomyces pombe, which has been suggested to act at the G1/S phase of the cell cycle. Cyclin G mRNA is induced within 3 h after growth stimulation and remains elevated with no apparent cell cycle dependency, indicating its close association with growth stimuli but not with the cell cycle.

Dephosphorylation of human p34cdc2 kinase on both Thr-14 and Tyr-15 by human cdc25B phosphatase

In mammalian cells, p34cdc2 kinase undergoes phosphorylation at threonine-14, tyrosine-15 and threonine-161 in the S and G2 phases of the cell cycle. At the onset of mitosis, the kinase becomes dephosphorylated at threonine-14 and tyrosine-15, resulting in activation. Cdc25 phosphatase has been shown to dephosphorylate tyrosine-15 in vitro, but whether it also does at threonine-14 remains unclear. In this study, we have found that human cdc25B phosphatase dephosphorylates both threonine-14 and tyrosine-15 but not threonine-161.

[Fluorescein fundus angiography of optic nerve head in primary open angle glaucoma and low tension glaucoma]

Fluorescein fundus angiography was performed at angle of 20 degrees in the 58 low tension glaucoma (LTG) eyes (30 cases) and 77 primary open angle glaucoma (POAG) eyes (41 cases) and the relation of the optic nerve head fluorescein changes to visual field disturbances (stage classification of Kosaki) was compared between POAG and LTG groups. The filling defect of fluorescein in the deep area and the decrease in number of superficial capillaries were observed in the optic nerve head. The filling defect area of fluorescein in the optic nerve head corresponding to Bjerrum scotoma was recognized even in the mild visual field disturbance cases of both LTG and POAG. The following findings were noted in both LTG and POAG cases; expansion of the filling defect area and the decrease in number of superficial capillaries in the same area with progression of visual field disturbances. Filling defect area of fluorescein of the optic nerve head accorded with visual field disturbance area in 19 LTG eyes (32.8%) and 61 POAG eyes (79.2%). On the contrary, the filling defect area of the optic nerve head was wider than the visual disturbance area in 37 LTG eyes (63.8%) and 16 POAG eyes (20.8%). These findings suggest that blood circulatory disorders of the optic nerve head occurred earlier in LTG than in POAG and that the development of LTG might be closely associated with the blood circulatory disorders.

Generation of plasma kinin by three types of protease isolated from Porphyromonas gingivalis 381

Three types of protease (A, B and C) isolated from the culture supernatant of Porphyromonas gingivalis 381 had peculiar activities on kinin generation from high molecular-weight kininogen in vitro. Protease C released bradykinin from the kininogen in a reaction mixture containing 2 mM dithiothreitol, but A and B did not. However, the activity of degrading bradykinin was much stronger in protease A and B than in C. These findings suggest that only protease C shows plasma kallikrein activity.

Elongation factor-1 alpha gene determines susceptibility to transformation

Elongation factor-1 alpha (EF-1 alpha), an essential component of the eukaryotic translational apparatus, is a GTP-binding protein that catalyses the binding of aminoacyl-transfer RNAs to the ribosome. Expression of the EF-1 alpha gene decreases towards the end of the lifespans of mouse and human fibroblasts, but forced expression of EF-1 alpha prolongs the lifespan of Drosophila melanogaster. Eukaryotic initiation factor-4E, another component of the translational machinery, is mitogenic or oncogenic when constitutively expressed in some mammalian cells. Thus, components of the protein synthesis apparatus seem to be involved in the control of cell proliferation. Using expression cloning, we have isolated a complementary DNA clone from a BALB/c 3T3 mouse fibroblast variant, A31-I-13 (ref. 10), which specifies a factor determining the susceptibility of BALB/c3T3 to chemically and physically induced transformation. Here we report that the factor is EF-1 alpha and that its constitutive expression causes BALB/c 3T3 A31-I-1 (ref. 10), C3H10T1/2 (ref. 11) and Syrian hamster SHOK fibroblasts to become highly susceptible to transformation induced by 3-methylcholanthrene and ultraviolet light. EF-1 alpha messenger RNA is also constitutively expressed in a quiescent culture of the highly susceptible variant A31-I-13. We conclude that the removal of regulation of the expression of these components of the translational machinery may predispose cells to become more susceptible to malignant transformation.