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Biomedical subjects

K Murai

Publications and source records attributed to K Murai.

At least 55 records · Page 3Linked to original sources
PubMed1998

Uncontrolled diabetes hinders bone formation around titanium implants in rat tibiae. A light and fluorescence microscopy, and image processing study.

This study examined the influence of diabetes mellitus on bone formation around cylindrical titanium (Ti) implants (1.0 mm in diameter and 1.5 mm in length) inserted transcortically and extending into the medullary canal of rat tibiae using light and fluorescence microscopies and image processing. Forty-eight male Wistar King A rats (age 5 weeks) were used in this experiment. Streptozotocin was injected intraperitoneally to induce diabetes and the serum glucose concentration was checked to ensure the induction of diabetes prior to implant placement and at the time of sacrifice. The animals were sacrificed 7, 28, 56, or 84 days after placement. Toluidine blue-stained undecalcified sections were prepared for histological observation and image analysis. The Ti implants in the control group became increasingly encapsulated with a bone layer. The implants in the diabetes-induced (DI) group were also surrounded with a thin bone layer. Abundant adipocytes were observed in the DI group as compared with the control group. Quantitative evaluation indicated that the control group showed a significantly higher percent of bone contact, and thickness of surrounding bone and area than the DI group. Consequently, the present study suggests that uncontrolled diabetes would hinder bone formation around Ti implants in rats.

Adipocytes↗
PubMed1998

[Hemophagocytic syndrome due to miliary tuberculosis in the course of aplastic anemia].

We report a 63 year-old female with aplastic anemia (AA) who was complicated with hemophagocytic syndrome induced by systemic miliary tuberculosis. Two years before admission to our hospital, she was diagnosed as AA and had been treated with granulocyte colony-stimulating factor, erythropoietin and methenolone acetate. In May, 1996, She was transferred to our hospital because of high fever and exacervation of pancytopenia. She showed severe pancytopenia, and an increase in macrophages showing remarkable erythrophagocytosis and decrease in hemopoietic cells in the bone marrow. In initial examination, high titer of IgM antibody to herpes simplex virus type I was identified and methylprednisolone pulse therapy was started under the diagnosis of virus associated hemophagocytic syndrome. Ten days later, however, she died for intestinal hemorrhage followed by multiorgan failure. In autopsy, multiple epitheloid cell granulomas with acid-fast bacilli were found in bone marrow, lungs, liver, spleen and kidneys.

Anemia, Aplastic↗
PubMed1997

Cellular delivery of neurotrophin-3 promotes corticospinal axonal growth and partial functional recovery after spinal cord injury.

The injured adult mammalian spinal cord shows little spontaneous recovery after injury. In the present study, the contribution of projections in the dorsal half of the spinal cord to functional loss after adult spinal cord injury was examined, together with the effects of transgenic cellular delivery of neurotrophin-3 (NT-3) on morphological and functional disturbances. Adult rats underwent bilateral dorsal column spinal cord lesions that remove the dorsal corticospinal projections or underwent more extensive resections of the entire dorsal spinal cord bilaterally that remove corticospinal, rubrospinal, and cerulospinal projections. Long-lasting functional deficits were observed on a motor grid task requiring detailed integration of sensorimotor skills, but only in animals with dorsal hemisection lesions as opposed to dorsal column lesions. Syngenic primary rat fibroblasts genetically modified to produce NT-3 were then grafted to acute spinal cord dorsal hemisection lesion cavities. Up to 3 months later, significant partial functional recovery occurred in NT-3-grafted animals together with a significant increase in corticospinal axon growth at and distal to the injury site. These findings indicate that (1) several spinal pathways contribute to loss of motor function after spinal cord injury, (2) NT-3 is a neurotrophic factor for the injured corticospinal projection, and (3) functional deficits are partially ameliorated by local cellular delivery of NT-3. Lesions of the corticospinal projection may be necessary, but insufficient in isolation, to cause sensorimotor dysfunction after spinal cord injury in the rat.

Animals↗
PubMed1997

Increased expression of interleukin-2 receptor alpha on peripheral blood mononuclear cells in HTLV-I tax/rex mRNA-positive asymptomatic carriers.

Using the double-nested reverse transcription-polymerase chain reaction, we assayed human T-cell leukemia virus type I (HTLV-I) tax/rex-encoded mRNA in the peripheral blood mononuclear cells (PBMCs) of asymptomatic carriers as an index of the expression of HTLV-I in vivo in relation to the proviral DNA level. HTLV-I tax/rex mRNA was detected in only 1 (3.3%) of 30 samples with medium or lower proviral DNA levels, but it was detected in 11 (39.3%) of 28 samples with high HTLV-I proviral DNA levels, estimated as equal to or more than the proviral DNA of 10 ng of HUT102 (i.e., HUT102 cells were used as positive controls). The mean number of interleukin-2 receptor alpha (IL-2R alpha)-positive cells as a percentage of the total number of PBMCs was higher (13.2%) in the tax/rex mRNA-positive carriers with high proviral DNA levels than in the carriers who were mRNA negative (8.4%) (p = 0.004, Wilcoxon test). These results suggest that virus activation as indicated by the presence of tax/rex mRNA in asymptomatic carriers with high proviral DNA levels is associated with an elevation of the IL-2R alpha-positive cells in vivo.

Carrier State↗
PubMed1997

Effects of aging on titanium implants inserted into the tibiae of female rats using light microscopy, SEM, and image processing.

We examined the influence of aging on the implant-bone interface of titanium implants inserted transcortically and extending into the medullary canal of rat tibiae, and quantitatively assessed the differences in bone reaction using an image processing system. Three groups of 15 female rats, aged 6 weeks (young group), 22 weeks (adult group), and 80 weeks (old group) were used in this experiment. The animals were sacrificed 28 days after implant placement. Toluidine blue stained undecalcified sections were prepared for histological observation and image analysis, and the implant socket was observed by SEM. There was no difference in the degree of maturation of newly formed bone between the young and adult groups. Titanium implants inserted in the young and adult groups were surrounded with a bone layer. In the old group, however, there was little mature bone tissue around the implants. Quantitative evaluation indicated that the young group showed the highest, the adult group showed a slightly lower, and the old group showed the lowest percent bone contact, thickness of bone contact, and area of bone surrounding the implant.

Aging↗
PubMed1997

Long-term evaluation of bone-titanium interface in rat tibiae using light microscopy, transmission electron microscopy, and image processing.

We conducted a 2-year histologic and histometric evaluation of the tibial bone-titanium (Ti) implant interface in male rats. Thirty male 6-week-old rats were used in this study. They were divided into two groups: 15 for day 28 and 15 for day 730. Microscopic observation at day 28 revealed that the newly formed bone around the implant almost surrounded the implant, but fibroblastlike cells were interposed in some histologic sections. At day 730, in contrast, such cells were rarely seen, and the bone around the implant presented a lamellar structure. Transmission electron microscopic observation at day 28 disclosed mature or poorly mineralized bone near the implant; however, an electron-dense amorphous zone about 50 nm in thickness was interposed between the bone and Ti. In places slender cells were interposed between the bone and Ti. The amorphous zone was also observed at the cell-Ti interface. At day 730, a poorly mineralized layer remained in some areas between the mature bone and the titanium, and the interposed amorphous zone was still observed. Occasionally, a 200-nm-thick layer, thought to be cell remnant, was seen. As calculated in an image-processing, system analysis, the percent bone contact and the thickness and area of the surrounding bone for the Ti implant at day 28 were 43.6%, 30.4 microns, and 0.10 mm2, respectively, and those at day 730 were 89.9%, 53.5 microns, and 0.19 mm2, respectively. In summary, although the passage of time may affect bone maturity, interfacial cells remain at the bone-Ti interface as a uniform layer together with unmineralized bone.

Animals↗
PubMed1997

Alloplasmic wheats with Aegilops crassa cytoplasm which express photoperiod-sensitive homeotic transformations of anthers, show alterations in mitochondrial DNA structure and transcription.

Alloplasmic wheat. Triticum aestivum cv. Norin 26, with Aegilops crassa cytoplasm, shows photoperiod-sensitive cytoplasmic male sterility (PCMS). This alloplasmic line expresses pistillody of anthers only when grown in long-day conditions (> 15 h light). To assess the molecular basis of the PCMS, we carried out Southern and Northern hybridization analyses on mitochondrial DNAs and RNAs isolated from seedlings of alloplasmic lines showing various PCMS phenotypes using probes for twelve mitochondrial genes. All RFLP patterns of mitochondrial DNA from alloplasmic lines greatly differed from those of common wheat, and were slightly changed from those of the parental species, i.e., Ae. crassa. This indicates that nuclear substitutions between related plant species induce structural alterations in the mitochondrial genome. Furthermore, RFLP patterns of (cr)-N61 and FR-mutant probed with coxIII and orf25 were identical with each other, but different from those of the other alloplasmic lines, indicating that the nuclei of N61 and FR-mutant harbor some gene(s) that induces structural alterations of the mitochondrial genome in the coxIII and orf25 regions. The transcription patterns of atp6 and cob in Ae. crassa type were different from those of T. aestivum type. Furthermore, the orf25 transcript in alloplasmic wheats was about 300 nucleotides longer than that of euplasmic lines, including the Ae. crassa pure line, suggesting that transcription patterns of orf25 are associated with recovery from the PCMS phenomenon. These data clearly show the mutual cross-talk between the nuclear genome and chondriome. These observations raise the possibility that the dysfunction of mitochondria caused by the failure of a cooperative control of mitochondrial gene(s) expression influences the pathway of flower morphogenesis, especially in the process that determines organ identity.

Blotting, Northern↗
PubMed1997

A novel form of the myeloid-specific zinc finger protein (MZF-2).

BACKGROUND: Myeloid cell development is controlled by tissue-specific transcription factors. Human myeloid zinc finger protein (MZF-1) is a putative transcription factor containing 13 zinc fingers, and has been suggested that it regulates the development of neutrophilic granulocytes. RESULTS: Here, we have isolated the murine and human cDNAs which encode a novel form of MZF protein (MZF-2). Murine and human MZF-2 proteins consisted of 814 and 775 amino acids, respectively, and have identity of 75.3% between them. The C-terminal half of human MZF-2, carrying the zinc finger domains, was completely identical with that of human MZF-1, whereas the N-terminal half of MZF-2 was different from the corresponding region of human MZF-1, and was coded by distinct exons. MZF-2 mRNA was expressed in myeloid cells, particularly in the cells committed to the neutrophilic lineage, and down-regulated by G-CSF. CONCLUSIONS: MZF-1 and MZF-2 mRNAs seem to be produced by the alternative use of two different transcription initiation sites. The distinct N-terminal half of MZF-2 carries two characteristic domains, a leucine-rich domain called LeR and an acidic domain, which suggests a unique function of MZF-2 in neutrophil development.

Amino Acid Sequence↗
PubMed1997

Two mechanisms in the action of repressor deltaEF1: binding site competition with an activator and active repression.

BACKGROUND: Counteraction between activators and repressors is crucial for the regulation of a number of cell-specific enhancers, where an activator and a repressor are mutually competitive in binding to the same site. DeltaEF1 is a repressor protein of delta1-crystallin minimal enhancer DC5 binding at the CACCT site, and inhibits activator deltaEF3 from binding to the overlapped site. It has two zinc finger clusters N-fin and C-fin, close to N- and C-termini, respectively, and a homeodomain in the middle. deltaEF1 also binds to the E2-box sequence CACCTG, and represses E2-box-dependent enhancers. RESULTS: The mechanism of the repressor action of deltaEF1 was investigated by examining various deletion mutants of deltaEF1 for their activity to repress delta1-crystallin enhancer fragment HN which contained DC5 sequence and an additional activator site. Both zinc finger clusters were found to be essential for DNA binding and repression, but the homeodomain was not. In addition, the NR domain close to the N-terminus was required for full repression. The NR domain showed active repression when fused to the Gal4 DNA binding domain. Active repression by deltaEF1, dependent on the NR domain, was also demonstrated in a situation where the binding sites of deltaEF1 and deltaEF3 were separated. N-fin and C-fin in their isolated forms bind the 5'-(T/C)ACCTG-3' and 5'-(t/C)ACCT-3' sequences, respectively, while the homeodomain showed no DNA binding activity. An analysis of DNA binding of the delta(Int)F form, having both N-fin and C-fin, indicated that a single DNA binding domain is assembled from two zinc finger clusters. CONCLUSION: Two mechanisms are involved in the repressor action of deltaEF1. First, a binding site competition with an activator which depends on the integrity of both zinc finger clusters, and second, an active repression to silence an enhancer which is attributed to the NR domain.

Adenovirus E2 Proteins↗
PubMed1997

Prevalence of genotypes of Orientia tsutsugamushi in patients with scrub typhus in Miyazaki Prefecture.

The genotypes of Orientia tsutsugamushi in patients with scrub typhus in Miyazaki Prefecture were examined by polymerase chain reaction (PCR) and the restriction fragment length polymorphism method. Specific patterns for genotypes Irie, Hirano, Tazume and Yoshimura were detected in 26, 6, 5 and 2 of 39 DNA samples obtained from peripheral blood mononuclear cells, respectively. DNA sequences of the PCR products from the Tazume strain were genetically very close to the Hirano strain and the Yoshimura strain was also very close to the Karp strain. Furthermore, the DNA sequences from the Irie and Tazume strains were completely homologous to the reported sequences of the Kawasaki and Kuroki strains, respectively.

Base Sequence↗
PubMed1997

Investigation of the 4,000-Hertz dip by detailed audiometry.

It is well known that a 4,000-Hz dip is often observed in the initial stage of noise-induced hearing loss and acoustic trauma, but it does not always occur as a result of these causes, and quite often the cause is unknown. Pure tone audiograms of 159 patients (76 cases of noise-induced hearing loss, 62 cases of hearing loss of unknown cause, 21 cases of familial hearing loss) with a 4,000-Hz dip were studied by detailed audiometry to clarify this configuration. The types of dip were classified into 11 groups; however, the basic types are the cone type, bowl type, and dish type, which show the smooth line of the hearing threshold. There were no clear differences in dip configuration among the 3 causes of hearing loss. It was thought that the dips displayed similar configurations regardless of the cause.

Adolescent↗
PubMed1997

Audiologic features of hearing loss due to the 1,555 mutation of mitochondrial DNA.

We proved a 1,555 mutation of mitochondrial DNA in one member of each of three families with familial streptomycin hearing loss, and report the pedigrees and audiologic features. DNA was extracted by the standard method. The 1,555 A to G mutation was identified in all three patients and confirmed by direct sequencing of the polymerase chain reaction products by a cycle sequencing method. On audiograms, the hearing loss was sensorineural, bilateral, and symmetric, showing a high-tone loss or a profound loss particularly in the high-tone range, and the "symmetry law" of Langenbeck was applicable. The superimposed audiograms of members of one family did not cross themselves, proving the applicability of the "never-cross principle of audiograms."

Adult↗
PubMed1997

Wheat MADS box genes, a multigene family dispersed throughout the genome.

Polymerase chain reaction (PCR) with degenerate primers was utilized for partial cloning of the MADS box gene family from wheat (Triticum aestivum L.). PCR products corresponding to a part of the MADS box region were cloned and sequenced. Eleven individual clones sequenced were classified into seven types on the basis of the nucleotide sequence and five types on the deduced amino acid sequence, which included two wheat-specific MADS box protein sequences. RT-PCR analysis with degenerate primers revealed preferential expression of the MADS box genes in young spikes. Furthermore, genomic Southern blot analysis with degenerate PCR products as probes indicated that wheat MADS box genes constitute a multigene family and are dispersed throughout the genome.

Amino Acid Sequence↗
PubMed1997

The effects of diabetes on the interface between hydroxyapatite implants and bone in rat tibia.

We examined the influence of diabetes on the implant-bone interface of hydroxyapatite (HA) implants inserted transcortically and extending into the medullary canal of rat tibiae, and quantitatively assessed the differences in bone reaction using an image processing system. Forty male Wistar King A rats (aged 5 weeks) were used in this experiment; they were sacrificed 84 days after implant placement. Toluidine blue-stained undecalcified sections were prepared for histological observation and image analysis, and the labeled sections were observed by confocal laser scanning microscopy. The HA implants in the bone marrow area in the control group were completely encapsulated with a bone layer, and there were some osteoblast-like cells in the bone lacunae apposing the implant surface. The HA implants in the diabetes-induced (DI) group were partially surrounded with a thin bone layer, and there were some fibroblasts running parallel to the implant surface at areas of no bone contact. Quantitative evaluation indicated that the control group showed significantly higher bone contact rate, bone contact thickness, and bone contact area than the DI group. The DI group showed approximately 30% reduction in the percentage of bone contact and 50% reduction in the thickness and the area of surrounding bone tissue.

Animals↗
PubMed1997

Progressive retinitis-encephalitis due to ganciclovir-resistant cytomegalovirus associated with aplastic anemia.

A 29-year-old woman with aplastic anemia who complained of visual disturbances and pain in the right eyeball was diagnosed as having cytomegalovirus (CMV) retinitis based upon the characteristic retinal changes and isolation of CMV. She received treatment with ganciclovir (GCV), and the retinitis initially responded for several months. However, the patient was found to have CMV lesions in the left eye followed by neurological symptoms. The CMV isolated just before her death was approximately 20 times more resistant to GCV than that isolated previously, suggesting that the GCV-resistant CMV had developed during the long-term treatment with GCV.

Adult↗
PubMed1997

Detection of polyanion-restricted anti-histone antibodies in patients with systemic lupus erythematosus.

The nature of the antibodies responsible for lupus erythematosus (LE) cells in systemic lupus erythematosus (SLE) remains obscure. We examined whether polyanion-restricted anti-histone antibodies were present in serum of patients with SLE using Western blotting analysis. Dextran sulfate or alginate was used as a polyanion compound in place of DNA. Antibodies which recognized dextran sulfate-histone complexes were present in serum of patients with SLE (17/34, 50%). These antibodies were detected in most SLE patients positive for LE cells (17/18, 94%) but not in those negative for LE cells or in patients with other collagen diseases. Similar results were obtained using alginate-histone complexes as antigens for Western blotting analysis. The antibodies to dextran sulfate-histone or alginate-histone complexes in serum of SLE patients were completely absorbed by treatment of serum with DNA-histone complexes, while they were unaffected by treatment with DNA only. The presence of antibodies to free histones and dextran sulfate-histone complexes did not seem to be related to the titer of anti-single stranded DNA antibody and anti-double stranded DNA antibody. We demonstrated the presence of polyanion-restricted antibodies in SLE, which may be responsible for the LE factor.

Adolescent↗
PubMed1997

[Early establishment of bone marrow hypoplasia by antileukemic chemotherapy with concurrent rhG-CSF in a case of acute myelogenous leukemia complicated with intestinal perforation].

We report a case of 53-year-old man with acute myelogenous leukemia (M2) showing a karyotype of t(7;11) (p15;p15), del(10) (q11;q12), who was complicated with perforation of a duodenal ulcer during the antileukemic chemotherapy using behenoyl ara-C, daunorubicin, 6-mercaptopurine and prednisolone. As his bone marrow still showed high cell density and leukemic proliferation at the time of intestinal perforation, the therapeutic regimen was changed to a combination of behenoyl are-C and mitoxantrone, and daily rhG-CSF was concurrently administered for the purpose of early establishment of bone marrow hypoplasia. On the 8th day after the therapeutic regimen had been changed, his bone marrow became nearly aplastic, and complete remission was obtained on the 24th day. This case may indicate that the concurrent administration of cell-cycle specific antileukemic drugs and rhG-CSF is available for AML patients with emergent need of leukemic cell reduction.

Antineoplastic Combined Chemotherapy Protocols↗