Transplantation of new autologous biomaterials into jaw cleft

This study compared bone-marrow grafting using chondroid or fibula bone grafts transplanted into simulated alveolar bone defects in mice. The osteogenic procedure was also investigated. As an experimental model of the maxillary alveolar bone cleft, suitable for testing bone-inductive materials, a surgical trephine with a low-speed dental engine was used to form critical-sized defects in the pre-maxillary bones of male mice. Distraction osteogenesis was performed using an external fixation device. The osteotomy site was surrounded by an external callus, consisting of hyaline cartilage, that contained a large quantity of chondroid bone. Transplanted bone within chondroid bone was characterized by bone formation and remodelling 30 days post-transplantation, and bone adhesion following chondroid bone grafting was better than adhesion following fibula grafting. The present findings are the first to demonstrate the potential of chondroid bone transplantation as a new therapeutic system of bone grafting, suitable for bone substitution in craniofacial bone defects.

Lethal adenovirus infection in a patient who had undergone nonmyeloablative stem cell transplantation

We present a case of adenovirus (ADV) infection in a patient who had undergone nonmyeloablative stem cell transplantation (NST). A 50-year-old man with chronic myelogenous leukemia in the second chronic phase underwent NST from an HLA 2-loci-mismatched sibling. ADV hemorrhagic cystitis developed and progressed to lethal pneumonia. ADV was isolated from urine, bronchoalveolar lavage fluid, and postmortem specimens of kidney and liver. Because there are few reports of lethal pneumonia associated with ADV in Japan, we present the case and discuss the cause of and therapy for the infection.

Regulation of the level of Vesl-1S/Homer-1a proteins by ubiquitin-proteasome proteolytic systems

The vesl-1S/homer-1a gene is up-regulated during seizure and long term potentiation. Other members of the Vesl family, Vesl-1L, -2, and -3, are constitutively expressed in the brain. We examined the regulatory mechanisms governing the expression level of Vesl-1S protein, either an exogenously introduced one in COS7 or human embryonic kidney 293T cells or an endogenous one in rat brain neurons in cultures. In both cases, application of proteasome inhibitors increased the amount of Vesl-1S protein but not that of Vesl-1L, -2, or -3 protein. Deletion analyses revealed that the C-terminal 11-amino acid region was responsible for the proteolysis of Vesl-1S by proteasomes. Application of proteasome inhibitors promoted ubiquitination of Vesl-1S protein but not that of the Vesl-1S deletion mutant, which evaded proteasome-mediated degradation. These results indicate that ubiquitin-proteasome systems are involved in the regulation of the expression level of Vesl-1S protein.

New pulp biobleaching system involving manganese peroxidase immobilized in a silica support with controlled pore sizes

Attempts have been made to use manganese peroxidase (MnP) for chlorine-free pulp biobleaching, but they have not been commercially viable because of the enzyme's low stability. We developed a new pulp biobleaching method involving mesoporous material-immobilized manganese peroxidase from Phanerochaete chrysosporium. MnP immobilized in FSM-16, a folded-sheet mesoporous material whose pore size is nearly the same as the diameter of the enzyme, had the highest thermal stability and tolerance to H(2)O(2). MnP immobilized in FSM-16 retained more than 80% of its initial activity even after 10 days of continuous reaction. We constructed a thermally discontinuous two-stage reactor system, in which the enzyme (39 degrees C) and pulp-bleaching (70 degrees C) reactions were performed separately. When the treatment of pulp with MnP by means of the two-stage reactor system and alkaline extraction was repeated seven times, the brightness of the pulp increased to about 88% within 7 h after completion of the last treatment.

Analysis of histochemically and morphometrically in the anterior belly digastric muscle of osteopetrotic (op/op) mice

The fibers of the anterior belly digastric muscle of mice, fed a granulated diet for various periods, have been studied histochemically and morphometrically. The diameters of the anterior belly digastric fibers in normal mice fed only a granulated diet were smaller than those in mice fed a solid diet. Differences in the succinate dehydrogenase (SDH) activity of muscle fibers between op/op and normal mice gradually appeared in the anterior belly digastric muscle and, by the age of 90 days, under-development of muscle fibers was observed in the mild-belly region of the anterior belly digastric muscle of op/op mice fed a granulated diet. These results indicate mechanical stress in mastication plays an important role in the development of the anterior belly digastric muscle structures.

Phorbol esters promote postsynaptic accumulation of Vesl-1S/Homer-1a protein

We examined effects of phorbol esters on the amount and the subcellular distribution of the activity-regulated protein Vesl-1S/Homer-1a in cultured hippocampal neurons. Major Vesl-1S immunoreactivity (IR) was detected throughout neuronal somata under control conditions. Bath application of phorbol esters, PMA and PDBu resulted in the increase in the amount of Vesl-1S proteins and promoted punctate distribution of Vesl-1S IR at the cortical regions of the neuronal somata. Immunofluorescent observations using antisynaptophysin and anti-Vesl-1S antibodies, and electron microscopic observations, revealed that Vesl-1S accumulated at postsynaptic regions following PMA application. Membrane depolarization with high concentrations of external potassium also promoted the punctate distribution of Vesl-1S IR. These results demonstrate that phorbol-triggered reaction cascades result in the accumulation of Vesl-1S protein at postsynaptic regions, and suggest that these phorbol effects may mimic those caused by synaptic activities.

Haematopoietic progenitor cells from the common marmoset as targets of gene transduction by retroviral and adenoviral vectors

To establish a new non-human primate model for human cytokine and gene therapy, we characterized lymphocytes and haematopoietic progenitor cells of the small New World monkey, the common marmoset. We first assessed the reactions of marmoset bone marrow (BM) and peripheral blood (PB) cells to mouse anti-human monoclonal antibodies (mAbs) for the purpose of isolating marmoset lymphocytes and haematopoietic progenitor cells. Both cell fractions stained with CD4 and CD8 mAbs were identified as lymphocytes by cell proliferation assay and morphological examination. Myeloid-specific mAbs such as CD14 and CD33 did not react with marmoset BM and PB cells. No available CD34 and c-kit mAbs could be used to purify the marmoset haematopoietic progenitor cells. Furthermore, we studied the in vitro transduction of the bacterial beta-galactosidase (LacZ) gene into CFU-GM derived from marmoset BM using retroviral and adenoviral vectors. The transduction efficiency was increased by using a mixed culture system consisting of marmoset BM stromal cells and retroviral producer cells. It was also possible to transduce LacZ gene into marmoset haematopoietic progenitor cells with adenoviral vectors as well as retroviral vectors. The percentage of adenovirally transduced LacZ-positive clusters was 15% at day 4 (multiplicity of infection=200), but only 1-2% at day 14. The differential use of viral vector systems is to be recommended in targeting different diseases. Our results suggested that marmoset BM progenitor cells were available to examine the transduction efficiency of various viral vectors in vitro.

Prediction of osteonecrosis by magnetic resonance imaging after femoral neck fractures

Thirty-one patients undergoing internal fixation for femoral neck fractures who were examined by magnetic resonance imaging at 2, 6, and 12 months after surgery and who could be followed up more than 2 years were enrolled in the current study. The items investigated were timing of the appearance of the band image on T1 weighted images, magnetic resonance imaging classification, and plain radiographs. Band images were observed 2 months after surgery in eight patients and 6 months in 12 patients (39% of all patients). According to the location and extent of the band image on magnetic resonance imaging, one patient was classified in the B1 Group (lateral type), four patients in the B2 Group (surface type), three patients in the B3 Group (intermediate type), and four patients in the B4 Group (extended type). Band images appeared in all patients in the B4 Group 6 months after surgery. Femoral heads of the patients in the B3 and B4 Groups by magnetic resonance imaging classification all were collapsed. On plain radiographs, osteonecrosis of the femoral head could be diagnosed in eight patients between 11 and 24 months after injury. The interval giving the greatest sensitivity, specificity, and accuracy of the diagnosis of osteonecrosis of the femoral head by magnetic resonance imaging was 6 months after surgery.

Possible cause of G-C-->C-G transversion mutation by guanine oxidation product, imidazolone

BACKGROUND

The genome is constantly assaulted by oxidation reactions which are likely to be associated with oxygen metabolism, and oxidative lesions are generated by many types of oxidants. Such genotoxin-induced alterations in the genomic message have been implicated in aging and in several pathophysiological processes, particularly those associated with cancer. The guanine base (G) in genomic DNA is highly susceptible to oxidative stress due to having the lowest oxidation potential. Therefore, G-C-->T-A and G-C-->C-G transversion mutations frequently occur under oxidative conditions. One typical lesion of G is 8-oxo-7,8-dihydro-guanine (8-oxoG), which can pair with A. This pairing may cause G-C-->T-A transversion mutations. Although the number of G-C-->C-G transversions is rather high under specific oxidation conditions such as riboflavin photosensitization, the molecular basis of G-C-->C-G transversions is not known.

RESULTS

To determine which oxidative products are responsible for G-C-->C-G transversion mutations, we photooxidized 5'-d(AAAAAAGGAAAAAA)/5'-d(TTTTTTCCTTTTTT) using either riboflavin or anthraquinone (AQ) carboxylate under UV irradiation. Prolonged low-temperature (4 degrees C) enzymatic digestion of photoirradiated sample indicated that under both conditions the amount of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) initially increased with decreasing amounts of 2'-deoxyguanosine (dG), then decreased with the formation of 2-amino-5-[(2-deoxy-beta-D-erythro-pentofuranosyl)amino]-4H-imidazol-4-one (dIz), suggesting that nascent 8-oxoG was further oxidized to 2,5-diamino-4H-imidazol-4-one (Iz) in duplex DNA. Photoirradiation of an AQ-linked oligomer with a complementary strand containing 8-oxoG indicated that 8-oxoG residues were oxidized to Iz. These results indicate that Iz is formed from 8-oxoG through long-range hole migration. Primer extension experiments using a template containing Iz demonstrated that only dGTP is specifically incorporated opposite Iz suggesting that specific Iz-G base pairs are formed. The 'reverse' approach consisting of DNA polymerization using dIzTP showed that dIzTP is incorporated opposite G, further confirming the formation of a Iz-G base pair.

CONCLUSIONS

HPLC product analysis demonstrated that Iz is a key oxidation product of G through 8-oxoG in DNA photosensitized with riboflavin or anthraquinone. Photoreaction of AQ-linked oligomer confirmed that Iz is formed from 8-oxoG through long-range hole migration. Two sets of primer extension experiments demonstrated that Iz can specifically pair with G in vitro. Specific Iz-G base pair formation can explain the G-C-->C-G transversion mutations that appear under oxidative conditions.

The conformational study of chitin and chitosan oligomers in solution

The inter-residual dihedral angles phi and phip of chitin and chitosan oligomers were determined from experimental 3J(C-H) constants and ROESY cross peaks.

Amplification of bleomycin-induced DNA cleavage at cytosine residues 3' to GGG sequences by pyrrole triamide

We investigated the amplification of bleomycin-induced DNA cleavage by synthetic triamides containing N-methylpyrrole (Py) and/or N-methylimidazole (Im), PyPyPy, PyPyIm, PyImPy, and PyImIm, using 32P-labeled DNA fragments obtained from the human c-Ha-ras-1 and p53 genes. Peplomycin, a bleomycin analog, plus Fe(II) caused DNA cleavage at the 5'-GC-3' and 5'-GT-3' sequences (damaged bases are underlined). The addition of PyPyPy dramatically enhanced the cleavage, particularly at cytosine residues 3' to consecutive guanines. Alteration in the site specificity was not observed with other triamides (PyPyIm, PyImPy, and PyImIm). DNase I footprinting revealed that PyPyPy bound to the sites adjacent to the sites where DNA cleavage was enhanced by PyPyPy, and that PyPyPy enhanced DNase I-induced cleavage in GC-rich regions. These findings suggest that binding of PyPyPy to the DNA minor groove changes the DNA conformation to allow peplomycin to cleave DNA more efficiently at GC-rich sequences, resulting in intensive site-specific DNA cleavage particularly at cytosines at the 3'-side of polyguanines. The present study on amplifiers of antitumor drugs would appear to offer a novel approach to the establishment of more effective chemotherapy.

Kinetic analysis of microbial desulfurization of model and light gas oils containing multiple alkyl dibenzothiophenes

The reaction mechanism of biodesulfurization was investigated using whole cells of Rhodococcus erythropolis KA2-5-1, which have the ability to convert dibenzothiophene (DBT) into 2-hydroxybiphenyl. The desulfurization patterns of alkyl DBTs were represented by the Michaeis-Menten equation. The values of rate constants, the limiting maximal velocity (Vmax) and Michaelis constant (Km), for desulfurization of alkyl DBTs were calculated. The relative desulfurization activities of various alkyl DBTs were reduced in proportion to the total carbon numbers of alkyl substituent groups. Alkyl DBTs that had a total of six carbons of alkyl substituent groups were not desulfurized. The type or position of alkyl substituent groups had little effect on desulfurization activity. The desulfurization activity of each alkyl DBT, when mixed together, was reduced. This phenomenon was caused by apparent competitive inhibition of substrates. Using the apparent competitive inhibition model, the desulfurization pattern of a multiple components system containing alkyl DBTs was elucidated. This model was also applicable for biodesulfurization of light gas oil.

Prevalence of Cryptosporidium parvum infections in weaned piglets and fattening porkers in Kanagawa Prefecture, Japan

Fecal samples from 232 weaned piglets (1 and 3 months old) and 252 fattening porkers (6 months old) in 8 stock-raising farms located in Kanagawa Prefecture, Japan, from June 1998 to June 2000 were examined to determine the prevalence of Cryptosporidium infection. Detection of oocysts was performed using the ethyl acetate fecal concentration method and immunofluorescent staining. C. parvum oocysts were identified in 77 (33.2%) 1-3 months old weaned piglets from four farms. The odds of excreting among 1-3 months old piglets were more than 100 times greater than among 6 months old porkers (95% confidence interval: 17-902). This strongly suggests that weaned piglets are important reservoirs of pathogenic microbes whose potential contamination of drinking water has epidemiological implications for human health.

Trauma sites and clinical features associated with acute hyperextension spinal cord injury without bone damage--relationship between trauma site and severity

To elucidate whether a relationship exists between the site of trauma and severity of acute hyperextension spinal cord injury without bone damage, we examined the clinical features of 25 male and 10 female patients aged 13 to 88 years. None of the patients had vertebral damage such as fracture and dislocation. The site of impact was classified as the buccal, forehead, or mandibular region. The neurological findings were assessed according to Frankel's classification at admission and at follow up after 3 months or more to assess outcome. Eleven patients suffered trauma in the buccal region, one patient in Frankel's grade B, three in grade C, and seven in grade D at admission. All 11 of these patients showed an improvement of one grade or more to an outcome of C in one patient, D in one, and E in nine. Trauma occurred at the forehead region in 18 patients, four in grade B, 10 in grade C, and four in grade D. Improvement was seen at follow up by one grade or more to C in one patient, D in 10, and E in seven. Trauma occurred at the mandibular region in six patients, four in grade B and two in grade C. Four of these patients showed improvement of one grade or more to grade B in one, grade C in four, and grade E in one. Overall, seven patients had poor outcomes, five of whom suffered trauma to the mandibular region, indicating that impact to the mandibular region tends to have an unfavorable clinical outcome. Our findings indicate that the site of trauma greatly influences the severity of hyperextension spinal cord injury.

Mutagenic effects of 5-formyluracil on a plasmid vector during replication in Escherichia coli

PURPOSE

5-Formyluracil (5-foU) is a major derivative of thymine produced in DNA by ionizing radiation and various chemical oxidants. It has been previously shown that 5-foU in template DNA directs misincorporation of nucleotides by DNA polymerases during in vitro DNA synthesis. The present experiments were designed to understand the biological effects of5-foU in vivo.

MATERIALS AND METHODS

The modified base was incorporated site-specifically into the recognition site of restriction endonuclease SalI (5'-GTCGAC) or AflII (5'-CTTAAG) in vector plasmid pSVK3 and introduced the plasmid into Escherichia coli.

RESULTS

When the plasmids were replicated in E. coli, 5-foU caused mutations at the target sites. The induced mutation frequencies were 0.038-0.049%. Sequence analysis revealed that 5-foU preferentially caused T:A-->C:G and T:A-->A:T base substitutions and -1 deletions at the 5-foU site. 5-FoU also caused mutations at sites near the 5-foU. The alkA mutation did not affect the frequency of mutations in 5-foU-containing plasmids.

CONCLUSIONS

The present experiments demonstrated that 5-formyluracil in DNA caused mutations in E. coli.

Peroxisome proliferator-activated receptors are expressed in human cultured mast cells: a possible role of these receptors in negative regulation of mast cell activation

We investigated the expression of peroxisome proliferator-activated receptors (PPAR) in human cultured mast cells (HCMC) by using the reverse transcription-polymerase chain reaction. HCMC expressed mRNA of PPARbeta, gamma1, and gamma2 constitutively, whereas PPARalpha was not detected. Though PPARgamma2 was expressed weakly, activation of HCMC with anti-IgE after IgE sensitization or with calcium ionophore plus phorbol ester resulted in increased expression of PPARgamma2 specifically. These stimuli did not influence the expression of PPARalpha and beta. In addition, provocation of HCMC with IgE or with IL-4 increased the mRNA level of PPARgamma2, and a synergistic effect was observed with the combination of IgE plus IL-4. To investigate a possible role of PPAR in mast cells, we examined the effects of PPAR agonists on cytokine production by HCMC. Prostaglandin (PG) D(2), Delta(12)-PGJ(2), 15deoxy-Delta(12, 14)-PGJ(2) (15d-PGJ(2)), and troglitazone, all of which are PPARgamma agonists, attenuated the production of granulocyte-macrophage colony-stimulating factor by anti-IgE-stimulated HCMC. A similar effect was observed with carbaprostacyclin, a PPARbeta agonist, but not with PPARalpha agonists. Anti-IgE-induced expression of cytokine mRNA, such as TNF-alpha, IL-5 and macrophage inflammatory protein-1alpha mRNA, was also reduced by the treatment with these PPARgamma agonists. Though only Delta(12)-PGJ(2) and 15d-PGJ(2) revealed an inhibitory effect on histamine release, leukotriene C(4) release from HCMC was suppressed by all tested PPARgamma agonists. These results indicate that HCMC express PPARbeta and gamma1/2, which might negatively regulate the activation of HCMC.

Identification of repair enzymes for 5-formyluracil in DNA. Nth, Nei, and MutM proteins of Escherichia coli

5-Formyluracil (5-foU) is a potentially mutagenic lesion of thymine produced in DNA by ionizing radiation and various chemical oxidants. Although 5-foU has been reported to be removed from DNA by Escherichia coli AlkA protein in vitro, its repair mechanisms are not fully understood. In this study, we used the borohydride trapping assay to detect and characterize repair activities for 5-foU in E. coli extracts with site-specifically designed oligonucleotides containing a 5-foU at defined sites. The trapping assay revealed that there are three kinds of proteins that form covalent complexes with the 5-foU-containing oligonucleotides. Extracts from strains defective in the nth, nei, or mutM gene lacked one of the proteins. All of the trapped complexes were completely lost in extracts from the nth nei mutM triple mutant. The introduction of a plasmid carrying the nth, nei, or mutM gene into the E. coli triple mutant restored the formation of the corresponding protein-DNA complex. Purified Nth, Nei, and MutM proteins were trapped by the 5-foU-containing oligonucleotide to form the complex in the presence of NaBH(4). Furthermore, the purified Nth, Nei, and MutM proteins efficiently cleaved the oligonucleotide at the 5-foU site. In addition, 5-foU was site-specifically incorporated into plasmid pSVK3, and the resulting plasmid was replicated in E. coli. The mutation frequency of the plasmid was significantly increased in the E. coli nth nei mutM alkA mutant, compared with the wild-type and alkA strains. From these results it is concluded that the Nth, Nei, and MutM proteins are involved in the repair pathways for 5-foU that serve to avoid mutations in E. coli.

Amplification of pepleomycin-mediated DNA cleavage and apoptosis by unfused aromatic cations

An important approach to improve chemotherapy of members of the bleomycin (BLM) family of antibiotics is to find compounds (amplifiers) that enhance the activity of BLM-mediated DNA cleavage and apoptosis. Using a DNA-sequencing technique and pulsed field gel electrophoresis, we have investigated whether BLM-mediated cleavage of isolated and cellular DNA is amplifed by three compounds (RW-12, LS-20, 1S-5Me) which have a conformationally flexible, unfused polyaromatic system and cationic side chain in the molecules. RW-12 enhanced most effectively both pepleomycin (PEM)-induced cytotoxicity and apoptosis. The order of the maximum enhancing effect of amplifiers on PEM-mediated DNA damage is RW-12 > LS-20 > 1S-5Me. RW-12 amplified PEM-mediated DNA cleavage most effectively not only in vitro but also in cultured cells. We have reported that the order of the DNA binding constants of these compounds is RW-12 > LS-20 > 1S-5Me. In this study, we found a good correlation between PEM-mediated cleavage of isolated DNA and cellular DNA. These results suggest that BLM amplifiers bind to DNA and by doing so enhance drug-mediated DNA degradation, ultimately leading to apoptosis. The present study on amplifiers of anticancer agents shows a novel approach to the potentially effective anticancer therapy.

Syntheses of ketonated disulfide-bridged diruthenium complexes via C-H bond activation and C-S bond formation

The alpha-C-H bonds of 3-methyl-2-butanone, 3-pentanone, and 2-methyl-3-pentanone were activated on the sulfur center of the disulfide-bridged ruthenium dinuclear complex [(RuCl(P(OCH3)3)2)2(mu-S2)(mu-Cl)2] (1) in the presence of AgX (X = PF6, SbF6) with concomitant formation of C-S bonds to give the corresponding ketonated complexes [(Ru(CH3CN)2(P(OCH3)3)2)(mu-SSCHR1COR2)(Ru(CH3CN)3(P(OCH3)3)2)]X3 ([5](PF6)3, R1 = H, R2 = CH(CH3)2, X = PF6; [6](PF6)3, R1 = CH3, R2 = CH2CH3, X = PF6; [7](SbF6)3, R1 = CH3, R2 = CH(CH3)2, X = SbF6). For unsymmetric ketones, the primary or the secondary carbon of the alpha-C-H bond, rather than the tertiary carbon, is preferentially bound to one of the two bridging sulfur atoms. The alpha-C-H bond of the cyclic ketone cyclohexanone was cleaved to give the complex [(Ru(CH3CN)2(P(OCH3)3)2)(mu-SS-1- cyclohexanon-2-yl)(Ru(CH3CN)3(P(OCH3)3)2)](SbF6)3 ([8](SbF6)3). And the reactions of acetophenone and p-methoxyacetophenone, respectively, with the chloride-free complex [(Ru(CH3CN)3(P(OCH3)3)2)2(mu-S2)]4+ (3) gave [(Ru(CH3CN)2(P(OCH3)3)2)(mu-SSCH2COAr)(Ru(CH3CN)3(P(OCH3)3)2)](CF3SO3)3 ([9](CF3SO3)3, Ar = Ph; [10](CF3SO3)3, Ar = p-CH3OC6H4). The relative reactivities of a primary and a secondary C-H bond were clearly observed in the reaction of butanone with complex 3, which gave a mixture of two complexes, i.e., [(Ru(CH3CN)2(P(OCH3)3)20(mu-SSCH2COCH2CH3)(Ru(CH3CN)3(P(OCH3)3)2)](CF3SO3)3 ([11](CF3SO3)3) and [(Ru(CH3CN)2(P(OCH3)3)2)(mu-SSCHCH3COCH3)(Ru(CH3CN)3(P(OCH3)2)](CF3SO3)3 ([12](CF3SO3)3), in a molar ratio of 1:1.8. Complex 12 was converted to 11 at room temperature if the reaction time was prolonged. The relative reactivities of the alpha-C-H bonds of the ketones were deduced to be in the order 2 degrees > 1 degree > 3 degrees, on the basis of the consideration of contributions from both electronic and steric effects. Additionally, the C-S bonds in the ketonated complexes were found to be cleaved easily by protonation at room temperature. The mechanism for the formation of the ketonated disulfide-bridged ruthenium dinuclear complexes is as follows: initial coordination of the oxygen atom of the carbonyl group to the ruthenium center, followed by addition of an alpha-C-H bond to the disulfide bridging ligand, having S=S double-bond character, to form a C-S-S-H moiety, and finally completion of the reaction by deprotonation of the S-H bond.