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Biomedical subjects

H Ohyama

Publications and source records attributed to H Ohyama.

At least 73 records · Page 4Linked to original sources
PubMed1997

Comparison of in vitro proliferative capacity of human periodontal ligament cells in juvenile and aged donors.

OBJECTIVE: The aim of this study is to compare the in vitro proliferative capacity of periodontal ligament (PDL) cells from aged and juvenile donors. MATERIALS AND METHODS: Flow-cytometric analysis of the cell cycle was used to compare the length of each cell cycle, and the ratio of the cells progressing through the cycles between four PDL cells from juvenile donors and four cells from aged donors. Then, replicative capacity of the PDL cells from three juvenile and three aged donors was compared by serial cultures. Finally, expression of c-fos was compared between cells proliferating and cells which had reached senescent. RESULTS: Flow-cytometric analysis of the cell cycle had revealed that although there were no differences in the length of each phase of the cell cycle, significant differences were found in the ratio of the cells entering from Gap I to DNA synthesis phase of the cell cycle (P < 0.025). Replicative capacity was much longer in two cells from juvenile donors (about 20 population doublings), while all cells from aged donors showed short dividing abilities (less than eight population doublings), hence entered senescent phases shortly. Additionally, no c-fos was detected in cells which had reached senescence upon stimulation with serum. CONCLUSIONS: It is generally believed that aged humans have an impaired wound healing ability. We believe that more fibrotic PDL tissues seen in aged humans might be the reason for this, and suggest that this phenomena might be due to the progressive accumulation of senescent cell populations.

Adolescent↗
PubMed1996

Duration threshold of induced hypertension on cerebral blood flow, energy metabolism, and edema after transient forebrain ischemia in gerbils.

We have investigated whether there is a duration threshold for the effects of phenylephrine-induced hypertension on CBF, brain energy metabolism, and cerebral parenchymal specific gravity (SG) following transient forebrain ischemia in gerbils. Sixty gerbils were randomly assigned to one of the four treatment groups: one control group and three groups subjected to an increase of 25 mm Hg in MABP induced by treatment, 30 min after reperfusion, with phenylephrine for 15 min, 30 min, or 60 min. The local CBF was measured continuously, and the SG was evaluated 120 min after reperfusion. Sequential changes in brain energy metabolism, as shown by the ratio of phosphocreatine to inorganic phosphate (Pi), the beta-ATP/Pi ratio, and intracellular pH, were also measured. The 15-min induced hypertension regimen was most suited to the recovery of brain energy metabolism, which was associated with an increase in local CBF and a decrease in cerebral edema. These results demonstrate that a suitable duration can be chosen to optimize the beneficial effects of phenylephrine-induced hypertension on ischemic brain injury following transient forebrain ischemia.

Animals↗
PubMed1996

Assay for antiviral activity of herbal extracts using their absorbed sera.

We evaluated an antiviral assay procedure using serum obtained from guinea pigs administered 32 herbal extracts. In this assay, 21 of the 32 showed anti-herpes simplex virus type 1 (HSV-1) activity in serum. Ten of the 21 exhibited therapeutic anti-HSV-1 activity, and this was consistent with our previous results that 12 of the 32 were effective in murine infection models. Therefore, the serum pharmacological assay procedure was suitable for the selection of possible herbal extracts with biological activity in vivo as a pre-screening method before animal experiments.

Animals↗
PubMed1996

HLA Class II genotypes associated with early-onset periodontitis: DQB1 molecule primarily confers susceptibility to the disease.

DNA typing was performed on 24 Japanese patients with early-onset periodontitis (EOP) using the PCR-RFLP method to investigate an association of the susceptibility to EOP with the particular HLA class II alleles (HLA-DRB1, -DQA1, and -DQB1). DRB1*1401, DRB1*1501, DQB1*0503, and DQB1*0602 were found more frequently ("susceptible") in the EOP patients than in healthy controls. In contrast, DRB1*0405 and DQB1*0401 were found less frequently ("resistant") in EOP patients. All patients carrying DQB1*0602 had an atypical BamHI site in the intron upstream of the third exon of the DQB1 gene, which in our previous studies appeared to be a susceptible marker for EOP. A comparative analysis of the amino acid sequences of these susceptible and resistant HLA-DRB1 and DQB1 alleles elucidated some differences in antigen-derived peptide binding sites related to the susceptible or resistant alleles. Especially, DQB1*0503 and DQB1*0602 alleles carrying aspartic acid at position 57 and glycine at position 70 are increased significantly in EOP. Since amino acid residues at positions 57 and 70 on the DQB1 molecule are supposed to be involved in antigen binding, amino acid substitutions at these positions may affect the immune responsiveness to the periodontopathic antigen. Our results suggest that the DQB1 molecule plays a crucial role in the pathogenesis of EOP and that the susceptibility to EOP may be determined by the binding ability between the peptide and HLA-DQ antigens.

Adult↗
PubMed1996

[A case of endodermal cyst in front of the pontomedullary junction].

We reported a rare case of an endodermal cyst on the posterior fossa. The patient was a 51-year-old woman with tinnitus, ear blockage and a mild swallowing disturbance. MR images revealed a cystic mass 5 cm in diameter in front of the pontomedullary junction. Gadolinium-enhanced images showed some spotty lesions in the cystic mass. The brain stem was compressed strongly by the mass. The left vertebral artery was involved in the mass. Total removal of the tumor was performed via the transcondylar approach. During the operation the lower cranial nerves, the bilateral vertebral artery and the vertebral union were recognized. The cystic mass consisted of a yellow colored thin wall and a watery fluid which contained some small hard lesions. Histopathological examination of the cyst wall revealed a single layer of ciliated columnar epithelium, and that of the small lesions showed histiocytes and granulation. Immunohistochemically, the cyst wall was stained by an epithelial membrane antigen and a carcinoembryonic antigen. From these histopathological findings, the final diagnosis of the cystic lesion was an endodermal cyst. Twenty such cases have been reported to date since Afshar reported a case of an endodermal cyst on the posterior fossa in 1981. There are many types of cystic lesions in the intracranial region, and immunohistochemical studies are necessary for diagnosis of these intracranial cysts.

Brain Diseases↗
PubMed1995

Efficacy of traditional herbal medicines in combination with acyclovir against herpes simplex virus type 1 infection in vitro and in vivo.

Traditional herbal medicines have been safely used for the treatment of various human diseases since ancient China. We selected 10 herbal extracts with therapeutic antiherpes simplex virus type 1 (HSV-1) activity. Among these, Geum japonicum Thunb., Rhus javanica L., Syzygium aromaticum (L.) Merr. et Perry, or Terminalia chebula Retzus showed a stronger anti-HSV-1 activity in combination with acyclovir than the other herbal extracts in vitro. When acyclovir and/or a herbal extract were orally administered at doses corresponding to human use, each of the 4 combinations significantly limited the development of skin lesions and/or prolonged the mean survival times of infected mice compared with both acyclovir and the herbal extract alone (P < 0.01 or 0.05). These combinations were not toxic to mice. They reduced virus yields in the brain and skin more strongly than acyclovir alone and exhibited stronger anti-HSV-1 activity in the brain than in the skin, in contrast to acyclovir treatment by itself. Combinations of acyclovir with historically used herbal medicines showed strong combined therapeutic anti-HSV-1 activity in mice, especially reduction of virus yield in the brain.

Acyclovir↗
PubMed1995

Clinical and laboratory studies on a patient with early onset periodontitis and her family members. A case report.

Extensive clinical, microbiological, hematological, and immunological studies were performed on a patient with early onset periodontitis (EOP) and two other members of the family. The proband, a 27-year-old female, had early onset periodontitis and a high level of serum rheumatoid factors (RF) with no diagnosable medical disease. Her mother had lost all her teeth at the age of 50 because of advanced periodontitis, while her elder sister was unaffected by periodontitis. Neither the proband's periodontally-affected mother nor her unaffected sister exhibited a detectable level of RF. In this study, we examined: 1) serum immunoglobulin G (IgG) antibody titers against putative periodontal pathogenic bacteria; 2) peripheral neutrophil functions; 3) phenotypic analyses of peripheral lymphocyte subpopulations; and 4) peripheral lymphocyte functions (T cell proliferative activity, ability of cytokine [interleukin (IL)-2, tumor necrosis factor-alpha, interferon-gamma, IL-6 and IL-8] and IgG and IgM productivity). High antibody titers to Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Campylobacter rectus were detected in the sera of the proband, as were high serum antibody titers to P. gingivalis in the mother and to C. rectus in the unaffected sister compared to the non-periodontitis affected subjects. The proband also showed enhanced neutrophil chemotaxis; a high percentage of pan-B cells; and high productivity of IL-6, IgG, and IgM compared to individuals who were not periodontally affected. The mother showed slightly low helper/induced T cells (Th/i) suppressor/cytotoxic T cells (Ts/c) ratios due to the elevated count of Ts/c, and high IFN-gamma productivity compared to control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Age-related differences in synaptosomal membrane fluidity.

Fluidity of the lipid bilayer near the surface of the membranes and in the core of the lipid bilayer of synaptosomal membranes isolated from the cortex, hippocampus, striatum, hypothalamus, midbrain, pons-medulla oblongata and cerebellum of mice at 1, 2, 4, 12, and 18 months of age was examined using electron spin resonance spectrometry. Using the spin labels, 5- and 16-DS-stearic acid, the order parameter for 5-DS was found to be increased in all brain areas with aging and a much greater increase was found in the hippocampus and cerebellum at 18 months of age. The results demonstrated that there was a different pattern of the increase of the parameter between 15-DS and 16-DS in synaptosomal membranes of different brain regions with aging.

Age Factors↗
PubMed1994

Identification of an endonuclease responsible for apoptosis in rat thymocytes.

Analyses of cleavage ends of DNA fragments in apoptotic rat thymocytes induced by gamma-ray irradiation or by treatment with dexamethasone revealed that in both cases the fragments produced had 3'-hydroxyl (OH) and 5'-phosphoryl (P) ends of DNA chains. Rat thymocyte nuclei contained at least three endonuclease activities (deoxyribonucleases alpha, beta and gamma) that were able to cleave chromatin to mononucleosomal and oligonucleosomal fragments. The nuclei of apoptotic rat thymocytes induced by gamma-ray irradiation or dexamethasone retained considerable deoxyribonuclease gamma activity, but not alpha or beta deoxyribonuclease activity. During the induction of apoptosis, treatment with cycloheximide, which suppressed apoptosis, resulted in marked decreases of deoxyribonucleases alpha and beta activities. After release of cycloheximide inhibition, DNA fragmentation associated with apoptosis occurred in the cycloheximide-treated thymocyte nuclei, in which deoxyribonuclease gamma activity was only observed. The purified deoxyribonucleases alpha and beta were divalent cation-independent acidic endonucleases, which were separated on a CM5PW column by HPLC. The molecular masses of deoxyribonucleases alpha and beta were 28 kDa and 30 kDa, respectively, as determined by TSK G-2000SW gel-filtration HPLC, and both were 32 kDa in molecular mass as determined by SDS/PAGE. In contrast, deoxyribonuclease gamma, a neutral endonuclease, required both Ca2+ and Mg2+ for full activity and was inhibited by Zn2+. The molecular mass of deoxyribonuclease gamma was 31 kDa and 33 kDa when measured by gel filtration and SDS/PAGE, respectively. Under these optimal conditions, deoxyribonuclease gamma was shown to produce 3'-OH/5'-P ends of nucleosomal DNA fragments, while deoxyribonucleases alpha and beta both formed DNA fragments with 3'-P/5'-OH ends. The ends formed by cleavage with deoxyribonuclease gamma were the same as those produced in apoptotic rat thymocytes. On the basis of these results, it seems likely that deoxyribonuclease gamma is responsible for internucleosomal cleavage of chromatin during thymic apoptosis.

Animals↗
PubMed1994

Changes of aggressive behavior and brain serotonin turnover after very low-dose X-irradiation of mice.

Social isolation has been widely described to induce compulsive aggressive behavior and produce a large decrease of brain serotonin turnover in male mice. The aggressiveness by isolation in mice has been often used as a means for a better understanding of disturbed behavior in human beings. We found that male ICR white Swiss mice exhibiting isolation-induced aggression became gradually calm and showed remarkably quiet behavior 7 to 10 days after whole body irradiation of very low-dose X-rays (5-15 cGy). Higher doses (25-35 cGy), however, could not induce such effects. We also obtained the data on brain biochemistry giving a further support for the above low-dose effects on the mouse behavior. Brain serotonin turnover which has been known to be related to aggressive behavior in 5 or 15 cGy irradiated mice was faster than in aggressive control animals.

Aggression↗
PubMed1994

Unique intronic variations of HLA-DQ beta gene in early-onset periodontitis.

Human leukocyte antigen (HLA) class II beta chain plays an important role in the recognition of foreign antigens in immune reactions. Different forms of immune reaction may be concerned with initiation and progression of infectious diseases such as periodontitis. In this study we examined the frequency of HLA class II serotype and the variation of HLA class II beta gene in periodontitis patients. HLA serotypic frequencies in 70 Japanese patients with periodontitis and 26 individuals with periodontal health were examined. No HLA serotype specific to any type of periodontitis was observed. In order to detect differences among some HLA serotypes, restriction fragment length polymorphism (RFLP) analysis was undertaken with cDNA probes for HLA-DR beta and HLA-DQ beta genes in 20 subjects (15 patients and 5 healthy individuals). Atypical BamHI and EcoRI restriction sites were found in the HLA-DQ beta gene from 3 patients with early-onset periodontitis. In addition to these 20 subjects, an additional 80 subjects (40 patients and 40 healthy individuals) were screened for the atypical BamHI restriction site using the polymerase chain reaction method. It was detected in 7 patients with early-onset periodontitis, 1 patient with adult periodontitis, and 3 healthy subjects. No clinical differences except age were found between patients with this gene variation and other patients. Interestingly, all 3 healthy subjects with this gene variation were from subjects whose family members developed early-onset periodontitis with the gene variation. Atypical BamHI and EcoRI restriction sites and 41-nt repeated sequence were found in the intron before the third exon of HLA-DQB gene. These results suggest that these intronic gene variations may be useful as gene markers for a subpopulation of early-onset periodontitis and might affect immune reactions such as antigen recognition.

Adolescent↗
PubMed1994

[A case report of interstitial pneumonia caused by granulocyte colony-stimulating factor].

Several clinical trials have demonstrated that granulocyte colony-stimulating factor (G-CSF) accelerates the recovery of neutropenia in chemotherapy-induced bone marrow suppression. In this report, we describe a 46-year-old female with glioblastoma multiforme who developed interstitial pneumonia due to administration of G-CSF during the phase of immunochemoradiotherapy-induced neutropenia. Thirty-three days after starting immunochemoradiotherapy (ACNU, VCR, IFN -beta, radiation), she developed neutropenia (1,000/microliters). Administration of G-CSF at doses of 125-250 micrograms/day led to an increase of peripheral neutrophil counts. Eleven days later, the patient developed sudden severe respiratory failure and cyanosis with worsening of lung shadows. Blood gas levels on room air were PaO2 49.3mmHg, PaCO2 28.0mmHg, and pH 7.46. At this time, her neutrophil count had risen to 26,080/microliters. LDH and alpha - HBD had also increased to 1,439 IU/l and 1,117IU/l respectively. Chest radiograph and CT scan demonstrated interstitial pneumonia. After treatment with methyl prednisolone, her respiratory symptoms were gradually resolved. A number of side-effects have been reported with granulocyte-macrophage colony-stimulating factor (GM-CSF). These include fluid retention with pericardial and pleural effusion, fever, bone pain, fatigue, and rash. This report also suggests that G-CSF might be a cause of interstitial pneumonia during the phase of immunochemoradiotherapy-induced neutropenia.

Brain Neoplasms↗
PubMed1994

[Radiation and apoptosis].

Apoptosis is a kind of programmed cell death, that is, intrinsically programmed "cell suicide process". Mammalian thymic lymphocytes, thymocytes, show a typical apoptosis immediately after a low dose irradiation. Apoptosis appears also during radiotherapy of tumor, especially of thymoma. Tumor suppressor gene such as p53 and oncogene such as bcl-2 are found to be closely related to apoptotic processes in a cell. Possible mechanisms underlying interrelationship between expression of these genes, apoptosis and carcinogenesis were discussed.

Animals↗
PubMed1994

Biochemical properties of the major outer membrane proteins of Porphyromonas gingivalis.

The major outer membrane proteins (MOMP) of 53 and 67 kDa were identified by sodium dodecyl sulphate-polyacrylamide gel electrophoresis in outer membrane enriched fractions of Porphyromonas gingivalis FDC 381 and ATCC 33277, respectively. The MOMP were purified by anion exchange and gel filtration chromatography after extraction with Zwittergent 3-14. Their reactivity to monoclonal antibodies and their amino acid composition were analysed. The N-terminal amino acid sequences of twenty residues of both purified MOMP were determined and compared with those previously reported for MOMP of other periodontopathic bacteria.

Amino Acid Sequence↗