Biomedical subjects
Publications and source records attributed to T Usui.
Some derivatives of bactobolin were prepared from bactobolin (1) by radical reduction and formation of the fused azetidine ring. The derivatives proved less active than the parent antibiotic 1 against bacteria, indicating that dichloromethyl group at C-3 position play an important role in biological activity.
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The author attempted to clarify the histological changes after exposure to ethyl alcohol of superior cervical ganglion (SCG) cells in chronological order. Adult rat SCGs in situ were immersed in ethyl alcohol for various durations and were observed under light microscopy after fixation and histological processes. In almost all cases, the visages of the cells were in devastated state, although the grade of inflammatory reaction depends on the duration of exposure to the ethyl alcohol. In cases of short-lasting immersion, only the cells located near the capsule showed the so-called coagulation necrosis and those at the center of SCG were not so severely affected. Inflammatory reactions characterized by cellular invasion was also determined by duration of ethyl alcohol exposure. Number of normal neurons decreased until 60 days after immersion. From this study, it was revealed that complete ethyl alcohol blocking of the SCG depends on the duration of immersion time and the days after this procedure.
For the successful management of an emergency appendectomy and abscess drainage in an Eisenmenger's patient with diffuse peritonitis, it may be preferable to use general anesthesia with awake intubation. Epidural anesthesia is commonly combined with this anesthetic management for emergency abdominal surgery. However, the combination of topical anesthesia with epidural anesthesia should be avoided for fear of toxicity of local anesthetics in a patient with complications due to Eisenmenger's syndrome.
A simple method was used for testing the antibiotic susceptibility of adherent bacteria to plastic surfaces. Pseudomonas aeruginosa, Serratia marcescens, and Proteus mirabilis cells adhering to the bottom of a plastic tissue culture plate were incubated in serially diluted antibiotic solutions. After 24-h incubation the solutions were removed and a fresh medium without antibiotics was added to each well. The viability of the cells was judged by their growth after a further 24-h incubation. In our assay system, we employed a short incubation time (1-h) involving adherence of bacteria to a surface for the purpose of minimizing the effect of the glycocalyx on antibiotic activity. Even if the bacteria did not form a biofilm, the minimal bactericidal concentrations for adherent bacteria (MBCADs) markedly elevated. The MBCADs of ofloxacin well correlated with the bacteriological eradication by ofloxacin treatment for urinary tract infections (UTIs) associated with indwelling urinary catheters, whereas the minimal inhibitory concentrations did not show a correlation. Kinetic studies showed that adherent Pseudomonas aeruginosa had a 2 h-lag time before logarithmically growing when these bacteria were incubated in Mueller-Hinton broth without antibiotics. The tolerance demonstrated by adherent cells is likely to play a role in the difficulties encountered in the antimicrobial chemotherapy of biofilm infections. Moreover, our assay system was considered to be useful in the therapeutic selection of antibiotics for these infections.
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PURPOSE: Production of extracellular matrix (ECM) by corneal endothelial cells is related to physiologic functions and pathologic conditions and is regulated by many cytokines, including transforming growth factor-beta (TGF-beta). In this study, the molecular mechanism of ECM production regulation by TGF-beta was investigated in cultured corneal endothelial cells. METHODS: The production of ECM components (laminin and fibronectin) was detected in cultured corneal endothelial cells by western blot analysis. To determine the signal transduction pathways, mutant TGF-beta type I receptor (TbetaR-I) and/or Smad protein family members (intracellular signal transducers in TGF-beta signaling) were overexpressed by transfecting their cDNA into the cultured cells, and the effects on ECM production were observed. RESULTS: The production of laminin and fibronectin was stimulated by treatment with TGF-beta1 or TGF-beta2. After transient transfection of cDNA of the constitutively active (CA) mutant of TbetaR-I, the production of laminin and fibronectin was stimulated even in the absence of TGF-beta. The transfection of the dominant negative mutant of TbetaR-I counteracted the effects of TGF-beta. These results confirm that TGF-beta directly stimulates ECM production from corneal endothelial cells through TbetaR-I. The ECM production stimulation by TGF-beta or CA TbetaR-I was accelerated by the overexpression of Smad2, Smad3, and/or Smad4 and inhibited by that of Smad7. These results show that TGF-beta signals connected to ECM production are regulated by Smad family members, located downstream of TbetaR-I. CONCLUSIONS: The results of this study show that TGF-beta stimulates ECM production from corneal endothelial cells through TbetaR-I and Smad family transducers.
PURPOSE: Matrix metalloproteinase-7 (MMP-7), one of the extracellular matrix-degrading metalloproteinases, plays an important role in carcinoma invasion and metastasis. Tissue inhibitor metalloproteinase-1 (TIMP-1), one of the inhibitors of MMP-7, regulates extracellular matrix turnover. MATERIALS AND METHODS: Gene expression levels of MMP-7 and TIMP-1 were examined in 20 prostate carcinomas after hormonal therapy and 12 benign prostate hyperplasias (BPH) by Northern blot analysis. Enzymatic activities of MMP-7 were examined in 7 prostate carcinomas and 1 BPH in the above prostate tissues by the method of caseinolytic zymography. These data were compared with the clinicopathological features. RESULTS: There were significant correlations between levels of MMP-7 mRNA or the ratio of MMP-7 mRNA/TIMP-1 mRNA and pathological stage (p <0.01), lymph node metastasis (p <0.05), histological differentiation (p <0.05), vascular invasion (p <0.05), and lymphatic invasion (p <0.05). Levels of MMP-7 mRNA and the ratio of MMP-7 mRNA/TIMP-1 mRNA were significantly increased in prostate carcinomas from patients with high levels of serum prostate specific antigen (PSA) (>10 ng./ml.) after hormonal therapy (p <0.05). The activation ratio of pro MMP-7 was elevated in the cases with advanced prostate carcinoma compared with those of organ-confined prostate carcinoma and BPH. CONCLUSION: These results suggest that MMP-7 may play an important role for invasion and metastasis in prostate carcinomas, and the balance between MMP-7 and TIMP-1 expression may relate to an invasive ability of prostate carcinomas.
The authors attempted to clarify the histological changes of superior cervical ganglion (SCG) cells in chronological order. Adult rat SCGs were injected with ethyl alcohol and were examined under light microscopy after fixation and histological processes. All neurons showed the so-called coagulation necrosis. Inflammatory reactions characterized by cellular invasion were delayed in contrast to ethyl alcohol exposure from outside of the ganglion capsule.
The effect of unilateral superior cervical sympathetic ganglionectomy on the contralateral ganglion was investigated in Sprague-Dawley male rats employing histological and morphometrical procedures. Neuronal cells showed cell enlargement and no change in the nuclear size and the cell number. Neuronal hypertrophy was due to innervation by some fibers of the contralateral half of organs which had been innervated by the ipsilateral ganglion.
Poly(glutamic acid)s carrying lactose- and N,N'-diacetylchitobiose residues were synthesized via a simple two-step procedure. The oligosaccharides were treated with ammonium hydrogen carbonate and the resulting N-beta-glycosylamine was coupled with pendant carboxyl groups of poly(L-glutamic acid) in the presence of a mixture of benzotriazol-1-yl-oxytris(dimethylamino)phosphonium hexafluorophosphate (BOP) and 1-hydroxybenzotriazole (HOBt) in dimethyl sulfoxide. The oligosaccharide incorporated as pendant N-glycosides was estimated by 1H-NMR spectroscopy to be 30 mol% (or 45 wt%) for lactose and 27 mol% (46 wt%) for chitobiose. The glycopolypeptide carrying N,N'-diacetyl-chitobiose inhibited hemagglutination activity of wheat germ agglutinin (WGA) much more strongly (about 10(6) times) than N,N'-diacetylchitobiose itself. The high activity is due to the cluster or high density effect of the glycopolypeptides.
BACKGROUND: The estramustine binding protein (EMBP) specifically binds to estramustine and was first discovered in the rat ventral prostate. However, the physiological property of EMBP in the human prostate still remains to be elucidated. To elucidate whether EMBP is interrelated with cellular proliferation in human prostatic carcinoma (PC), the change in EMBP immunostaining during luteinizing hormone-releasing hormone (LH-RH) analog administration or during Cis-platinum-based chemotherapy, and the difference in EMBP immunostaining between hormone refractory (hr-PC) and untreated PC were analyzed. METHODS: Forty-six patients with histologically proven untreated PCs (34 were treated with LH-RH analog and 12 were treated with chemotherapy as an initial therapy) and 14 with hr-PC were used in this study. PC tissues were obtained before and 3 months after the initial therapy. The changes in immunostainings for EMBP, proliferating cell nuclear antigen (PCNA), and nm23 protein were compared with the change in serum prostate-specific antigen (PSA) level and the histological response during the treatment. RESULTS: The increased EMBP expression was observed in tumors with high histological grade and high clinical stage as well as in hr-PC. In untreated PC, EMBP expression weakly correlated with PCNA or nm23 protein immunoreactivity. In PC receiving LH-RH analog, EMBP expression was significantly reduced after treatment, however, no significant changes were observed in PCNA or nm23 protein immunoreactivity. In addition, EMBP expression before the treatment significantly correlated with the serum PSA change, while PCNA expression and nm23 protein immunoreactivity did not. On the other hand, no significant relationship was observed between histological changes induced by the LH-RH analog and immunostainings for EMBP, PCNA, and nm23 protein before treatment. In PC patients receiving chemotherapy, immunostainings for EMBP, PCNA, and nm23 protein were not significantly changed during the treatment. EMBP immunoreactivity was significantly higher in hr-PC than in untreated PC with paralleled change of PCNA expression and nm23 protein immunoreactivity. CONCLUSIONS: These observations indicate that EMBP is androgen regulated in some PCs. However, EMBP expression is demonstrated even in hr-PC and is interrelated with cellular proliferation especially in hr-PC.
beta-N-acetyl-D-hexosaminidase from Nocardia orientalis catalyzed the synthesis of beta-D-GlcNAc-(1 --> 3)-beta-D-Gal-(1 --> 4)-beta-D-GlcNAc-OC6H4NO2-p (1) and beta-D-GlcNAc-(1 --> 6)-beta-D-Gal-(1 --> 4)-beta-D-GlcNAc-OC6H4NO2-p (2) with its isomer beta-D-Gal-(1 --> 4)-[beta-D-GlcNAc-(1 --> 6)]-beta-D-GlcNAc-OC6H4NO2-p (3) through N-acetylglucosaminyl transfer from N-,N'-diacetylchitobiose to p-nitrophenyl beta-N-acetyllactosaminide. The enzyme formed a mixture of trisaccharides 1, 2, and 3 in a ratio of 11:33:56. In the case, when an inclusion complex of p-nitrophenyl beta-N-acetyllactosaminide with alpha-CD was used, compounds 1, 2, and 3 were formed in a molar ratio of 24:63:13. The regioselectivity of glycosidase-catalyzed formation of the trisaccharide glycosides was substantially changed. It resulted not only in a significant increase of the proportion of the desired compounds 1 and 2 but also in the substantial increase of the overall yield of transfer products.
To clarify the site and mode of action of tumor necrosis factor (TNF) in the pituitary, we studied the effects, binding sites of TNF and its receptor mRNA in the two types of mouse pituitary-derived cell lines, AtT-20, ACTH-producing cells and TtT/GF, folliculo-stellate (FS)-like cells. First, we examined the expression of TNF receptor mRNA in these cells. Using Northern blot analyses with radiolabeled cDNA to murine TNF receptor p60 and p80 mRNAs as probes, we identified both types of mRNA in the poly(A)-containing RNA prepared from AtT-20 cells and p60 TNF receptor mRNA from TtT/GF. The identified mRNA were compatible in size with those detected in the immune-competent cells. Next, we studied the TNF-binding sites on these cells. Scatchard plot analysis of the significant binding of [125I]TNF revealed a single type of binding site with a Kd (dissociation constant) of 210 pM and 131 binding sites/cell on AtT-20. Similarly on TtT/GF, [125I]TNF showed 353 binding sites/cell with a Kd of 900 pM. [125I]TNF binding on both types of cells competed with TNF and lymphotoxin (TNF beta) in an equimolar fashion. Third, TNF stimulates ACTH synthesis in AtT-20 cells, while TNF increases immunoreactive interleukin (IL)-6 release from TtT/GF cells. These findings demonstrate that AtT-20 and TtT/GF cells are equipped with fully functional TNF receptor system, and suggest that ligand of the receptor, TNF alpha and/or TNF beta, can modulate ACTH synthesis and release as a direct hormonal effector on corticotrophs or indirect modulator through another paracrine mediator, such as IL-6 from FS cells.
Apoptosis is morphologically related to premature mitosis, an aberrant form of mitosis. Staurosporine, a potent protein kinase inhibitor, induces not only apoptotic cell death in a wide variety of mammalian cells but also premature initiation of mitosis in hamster cells that are arrested in S phase by DNA synthesis inhibitors. Here we report on the biochemical differences between the two phenomena commonly caused by staurosporine. Rat 3Y1 fibroblasts that had been arrested in S phase with hydroxyurea underwent apoptosis by treatment with staurosporine, whereas S-phase-arrested CHO cells initiated mitosis prematurely when similarly treated with a low concentration of staurosporine. Chromosome condensation occurred in both apoptosis (3Y1) and premature mitosis (CHO). However, neither formation of mitotic spindles nor mitosis-specific phosphorylation of MPM-2 antigens was observed in apoptosis of 3Y1 cells, unlike premature mitosis of CHO cells. The p34cdc2 kinase activated in normal and prematurely mitotic cells remained inactive in the apoptotic cells, probably because the active cyclin B/p34cdc2 complex was almost absent in the S-phase-arrested 3Y1 cells. The absence of intracellular activation of p34cdc2 in apoptosis was confirmed by immunohistochemical analyses using a specific antibody raised against Ser55-phosphorylated vimentin which is specifically phosphorylated by p34cdc2 during M phase. Furthermore, phosphorylation of histones H1 and H3, which is associated with mitotic chromosome condensation, did not occur in the apoptotic cells. These results indicate that the two phenomena, staurosporine-induced apoptosis and premature mitosis, are different in their requirement for p34cdc2 kinase activation and histone phosphorylation.
A new gene encoding a heat shock protein 70 family protein of Schizosaccharomyces pombe (Sp), named sks2+, was cloned as a weak suppressor for the K-252a-sensitive mutation, ucm1. The nucleotide sequence of sks2+ revealed an open reading frame of a 613-amino-acid (aa) protein. The deduced aa sequence of sks2+ showed significant homology with Saccharomyces cerevisiae (Sc) Ssb1p and Ssb2p responsible for protein synthesis by non-organelle-localized ribosomes, as well as with other proteins of the HSP70 family. The cells lacking the functional sks2+ gene were viable and showed no increased sensitivity to K-252a but grew slowly with an elongated morphology. These results suggest that the sks2+ gene product plays a role in the cell cycle progression and is able to confer drug resistance in a multicopy state.
The B cell-specific activator protein (BSAP) is a DNA-binding transcription factor expressed in pro-B, pre-B, and mature B cells but not in plasma cells. We explored the role of BSAP in B cell function by creating clones in a late B cell and a plasma cell line transfected with a BSAP expression plasmid. We found that the plasma cell line MPC11, which does not produce BSAP, is still permissive to BSAP production driven by heterologous promoter. Overexpression of BSAP in a late B cell line (CH12.LX.A2) and a plasma cell line augmented cell proliferation and led to greater suppression of Ig synthesis in a late B cell line than in the plasma cell line. The reduction was seen mostly in synthesis of a secretory form of Ig. Overexpression of BSAP reduced Blimp-1 expression in CH12.LX.A2 clones but not in MPC11 clones. In addition, overexpression of BSAP in CH12.LX.A2 cells suppressed spontaneous appearance of cells with high Syndecan-1 expression and high amounts of intracytosolic as well as secreted Ig synthesis. To corroborate the above findings, we cloned nontransfected CH12.LX.A2 cells and found reduced BSAP mRNA expression in the high Ig-secreting clones, which produced more Blimp-1 mRNA with greater Syndecan-1 expression than the low Ig-secreting clones. Taken together, these results indicate that BSAP expression is sufficient to reduce Ig production in late B cells; this effect is mediated in part by suppression of differentiation to cells of plasma-cell phenotype.