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Biomedical subjects

M Shimamura

Publications and source records attributed to M Shimamura.

At least 37 records · Page 2Linked to original sources
PubMed2001

Maintenance of condylar position using an occlusal splint after mechanical vibrating-traction of the TMJ.

Although adequate relief of excess mechanical loading to the joint has been accepted as one of the important treatment concepts in the orthopaedic field, a treatment method for the temporomandibular joint (TMJ) to relieve excess mechanical loading has not yet been established. This study aimed to clarify the effect of an occlusal splint on the maintenance of the distracted condylar position achieved by vibrating-traction method. Vibrating dynamic traction force was applied for 5 min to the right TMJ using vibrating-traction apparatus. A flat stabilization splint was adjusted to keep the mandibular position and the condylar displacement was evaluated for 6 h after the dynamic traction procedure. Mean vertical displacement of the mandibular right first molar immediately after the vibrating-traction for the six subjects was 156 microm (ranging from 141 to 179 microm). The calculated mean condylar displacement immediately after the traction was 480 mum and could be kept to be 381 mum even after 6 h by wearing the flat stabilization splint. From the results of this study, it was revealed that the mechanically tracted condylar position could be maintained by a flat occlusal splint. It was suggested that the vibrating-traction method followed by the provision of occlusal support might have a possibility to work as a mechanical relieving procedure for the TMJ.

Adult↗
PubMed2001

Major sites for the differentiation of V alpha 14(+) NKT cells inferred from the V-J junctional sequences of the invariant T-cell receptor alpha chain.

CD1d-restricted mouse NK1.1(+) TCR alpha beta(+) natural killer T (NKT) cells predominantly use an invariant TCR alpha chain encoded by V alpha 14 and J alpha 281 gene segments with a one-nucleotide N region. We found that NKT cells generated in the culture of fetal liver precursors possessed V alpha 14-J alpha 281 junctions that could be produced without the action of terminal deoxyribonucleotidyl transferase (TdT), indicating that NKT cells derived from fetal liver precursors are distinguishable from those from adult precursors with TdT expression. In fact, the frequency of the fetal-form sequences decreased with ageing. Surprisingly, the fetal-type sequences were predominantly observed in the lymphoid organs of athymic mice with the exception of bone marrow, where a sequence peculiar to the organ, with TdT-involved conversion from the invariant junction, was frequently present. These findings suggest that there are two independent sites of V alpha 14(+) NKT cell development, the hematopoietic organs throughout life (the developing liver and adult bone marrow) and, principally, the mature thymus.

Aging↗
PubMed2001

Effect of a thick palatal appliance on muscular symptoms in craniomandibular disorders: a preliminary study.

Several treatment modalities for myofascial pain dysfunction syndrome (MPD) are being used at present. However, from the standpoint of patients' quality of life, it would be reasonable to seek a more effective treatment modality. This study aimed to show clinical data of a preliminary study regarding the effect of a thick palatal appliance, designed to fill the palatal concavity with a thick resin base, on muscular symptoms in eighteen MPD patients. Shown here are the clinical results of two volunteer patients using palatal appliances of two different thicknesses. In this study, MPD patents were divided into the three following groups: 1. no-treatment group; 2. thick palatal appliance group; and 3. medication group. Based on the results of this study, it was suggested that the thick palatal appliance could bring about early improvement of MPD syndrome. It is suggested that the thickness of the palatal plate was an important factor in obtaining the clinical effect.

Adult↗
PubMed2001

Hodgkin's disease preceded by unique neurological symptoms.

This is the first case report of Hodgkin's disease (HD) which showed both remission and exacerbation of neurological signs before a confirmed diagnosis of HD. The episodes occurred three times and multiple lesions were involved. Immunoabsorption plasmapheresis and double filtration plasmapheresis were effective for the first episode, whereas, corticosteroids partly improved the second and third episodes. Fever and lymph node swelling were apparent afterward and she was diagnosed as having HD from a supraclavicular lymph node biopsy. The remaining neurologic deficits responded to chemotherapy and radiotherapy. The neurological symptoms were considered as a paraneoplastic syndrome of HD.

Adult↗
PubMed2001

[Treatment for recurrent paradoxical brain embolism through the patent foramen ovale].

We report here two patients with recurrent paradoxical brain embolism through the patent foramen ovale(PFO). The TIAs, which occurred frequently under antiplatelet therapy, resolved soon after commencing the anticoagulation therapy. Case 1, a 57-year-old woman, was diagnosed as having lacunar brain infarction and was treated with ticlopidine hydrochloride. Eleven months later, she suffered from frequent TIAs. Anticoagulation therapy was started after the presence of PFO was documented on transesophageal echocardiography(TEE). Thereafter, her TIA disappeared. Case 2 was a 67-year-old man with a history of lacunar brain infarction. Although he was treated with aspirin for 9 months, he showed transient monoplegia in his right leg. His TEE study also revealed the presence of PFO. After the anticoagulation therapy reached the proper level(PT-NR = 2), he never experienced the recurrence of TIA. If the antiplatelet therapy failed to prevent the recurrence of TIA, it is recommended to find out the presence of PFO which is a potential source of paradoxical brain embolism. In such a case, anticoagulation therapy should be instituted.

Aged↗
PubMed2000

Inhibition by 9alpha-fluoromedoroxyprogesterone acetate (FMPA) against mammary carcinoma induced by dimethylbenz[a]anthracene in rats and angiogenesis in the rabbit cornea - comparison with medroxyprogesterone acetate (MPA).

Medroxyprogesterone acetate (MPA) is currently used therapeutically in the treatment of mammary and endometrial carcinomas. In order to develop a more potent and useful drug, we synthesized the novel compound, 9alpha-fluoromedoroxyprogesterone acetate (FMPA), by fluorinating MPA, and we also previously reported that FMPA displays more potent anti-angiogenic activity in the chorioallantoic membrane assay than MPA. In the present study, we investigated (1) the effects of FMPA on rat mammary carcinomas induced by dimethylbenz[a]anthracene (DMBA) to determine the anti-tumor activity, (2) the effect on angiogenesis in rabbit corneal assays, and (3) compared these results with those for MPA. FMPA inhibited the growth of mammary carcinomas in a dose-dependent manner (7.5, 30 and 120 mg/kg). Almost complete involution of the carcinomas was observed at doses of 30 and 120 mg/kg. MPA also inhibited the growth of carcinomas at doses of 30 and 120 mg/kg, but no involution of carcinomas was observed even at 120 mg/kg. FMPA significantly and MPA to a lesser degree inhibited carcinogenesis at 120 mg/kg within their treatments. In rabbit corneal assays, FMPA significantly inhibited angiogenesis (IC50 value=0.085 microg/pellet). MPA also significantly inhibited angiogenesis (IC50 value=0.60 microg/pellet). From these results, we conclude that FMPA is potentially more effective in the treatment of mammary carcinomas than MPA.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2000

Visual event-related potentials in progressive supranuclear palsy, corticobasal degeneration, striatonigral degeneration, and Parkinson's disease.

To determine whether there are characteristic changes in event-related potentials (ERPs) in parkinsonian syndromes we studied 8 patients with progressive supranuclear palsy (PSP), 10 patients with corticobasal degeneration (CBD), 9 patients with striatonigral degeneration (SND), and 16 patients with idiopathic Parkinson's disease (PD) with a mean duration of illness shorter than 5 years in each group. A visual oddball paradigm was employed to elicit P300. P300 to the rare target and rare nontarget stimuli and reaction time (RT) to rare target stimuli in each group were compared with those in the corresponding age-matched normal control group and to each other after age correction. The correlation of P300 and RT to motor disability score was also studied. In PSP P300 amplitude was markedly reduced while in CBD P300 latency was prolonged. P300 amplitude to rare nontargets in SND and PD was attenuated. The mean RT in the PSP and the CBD group was significantly longer than in the other two groups. The mean RT in PD and P300 amplitude to rare nontargets in both CBD and PD showed significant correlation with the severity of motor disability. Simultaneous measurement of P300 and RT may yield useful supplementary information in facilitating diagnosis of parkinsonian syndromes in addition to clinical criteria.

Aged↗
PubMed2000

Characterization of tynorphin, a potent endogenous inhibitor of dipeptidyl peptidaseIII.

To find a more effective inhibitor than spinorphin (LVVYPWT), an endogenous factor derived from bovine spinal cord, we synthesized spinorphin analogues and assayed their inhibitory activity toward DPPIII among enkephalin-degrading enzymes. Tynorphin (VVYPW), an N-terminal and C-terminal truncated form of spinorphin, exhibited more potent inhibitory activity and an IC50 value of 0.086 +/- 0.05 microg/ml (n = 4), whereas structures smaller than four amino acid residues exhibited almost no or less activity, suggesting that a five amino acid structure containing a Tyr-Pro residue is essential for the inhibition. The inhibition of DPPIII by tynorphin was predominantly competitive and the Ki value was found to be 7. 50 +/- 1.19 x 10(-8) M on Lineweaver-Burk plotting. The inhibitory activity of tynorphin toward other enkephalin-degrading enzymes such as neutral endopeptidase, aminopeptidase, and angiotensin-converting enzyme was not as high as that toward DPPIII, suggesting that tynorphin is a specific inhibitor of DPPIII. In HPLC analysis, human serum cleaved tynorphin rapidly (38% of control at 2 h and background level at 4 h), but in the presence of leuhisitin, an aminopeptidase inhibitor, tynorphin was maintained at the original level for 24 h. These results indicated that tynorphin had a more effective structure for expression of inhibitory activity toward DPPIII.

Animals↗
PubMed2000

Identification of a novel HLA-B46 allele, B*4602, in Japanese.

The B*4602 was identified in a healthy Japanese donor. The B46 variant antigen differed serologically from B46. The nucleotide sequence of B*4602 differed from that of B*4601 by a single base (from A to G) at position 293 in exon 2. The substitution changed the amino acid Asp at position 74 to Gly. The gene frequency of B*4602 in the Japanese population is extremely low. The presumed haplotype of B*4602 was HLA-A2-Cw1-B*4602-DRB1*09. This is the first report of polymorphism of the B46 antigen.

Alleles↗
PubMed2000

Two independent pathways of maternal cell transmission to offspring: through placenta during pregnancy and by breast-feeding after birth.

Cell transmission from mother to offspring was demonstrated using mice with green fluorescent protein (GFP) transgenic markers. GFP transgene heterozygous (+/-) females were mated with GFP (-/-) males, and GFP(+) cells in the GFP (-/-) fetuses generated between them were analysed to assess maternal blood cell transmission to conceptuses in utero. The GFP+ maternal cells were observed throughout the body of the fetuses, as shown by fluorescence stereomicroscopy. Cell entrance into the fetal immune system was shown by histochemical and flow cytometric analyses of fetal organs such as thymus, spleen and liver. The GFP(+) maternal cells persisted in the offspring until postpartum. Next, GFP (-/-) neonates fed by GFP(+) foster mothers were examined to study the transfer of maternal milk leucocytes to offspring through breast-feeding. GFP(+) leucocytes that had infiltrated through the wall of the digestive tract were mainly localized in the livers of neonates. Their accumulation in the livers reached a maximum on days 5 or 6, and these cells became undetectable, as assessed by either histochemistry or flow cytometry, after day 9 of starting foster nursing. Collectively, the present results demonstrate two independent pathways of maternal cell transmission to offspring: transplacental passage during pregnancy and breast-feeding after birth.

Animals↗
PubMed2000

Consistency of SINE insertion topology and flanking sequence tree: quantifying relationships among cetartiodactyls.

Short interspersed nuclear elements (SINEs) have been used to generate unambiguous phylogenetic topologies relating eukaryotic taxa. The irreversible nature of SINE retroposition is supported by a large body of comparative genome data and is a fundamental assumption inherent in the value of this qualitative method of inference. Here, we assess the key assumption of unidirectional SINE insertion by comparing the SINE insertion-derived topology and the phylogenetic tree based on seven independent loci of five taxa in the order Cetartiodactyla (Cetacea + Artiodactyla). The data sets and analyses were largely independent, but the loci were, by definition, linked, and thus their consistency supported an irreversible pattern of SINE retroposition. Moreover, our analyses of the flanking sequences provided estimates of divergence times among cetartiodactyl lineages unavailable from SINE insertion analysis alone. Unexpected rate heterogeneity among sites of SINE-flanking sequences and other noncoding DNA sequences were observed. Sequence simulations suggest that this rate heterogeneity may be an artifact resulting from the inaccuracies of the substitution model used.

Animals↗
PubMed2000

[Cerebral embolism in systemic lupus erythematosus with Libman-Sacks endocarditis: a case report].

We presented a patient of cerebral embolism caused by Libman-Sacks endocarditis with systemic lupus erythematosus (SLE). This 35-year-old housewife with SLE suffered from abrupt visual disturbance in December 1998. Angiography revealed the occlusion of her right posterior cerebral artery. Transesophageal echocardiography showed the mitral regurgitation and hyperplasia of the anterior mitral valve leaflet without vegetation. In April 1999, she again suffered from sudden onset of transient left hemiparesis and dysphasia. Angiographic findings were unchanged. Transesophageal echocardiographic examination detected vegetation on the anterior mitral valve leaflet and aggravation of the mitral regurgitation. Laboratory examination revealed inactivity of SLE. No bacteria was recovered from repeated blood cultures. We diagnosed that Libman-Sacks vegetation caused cerebral embolism.

Adult↗
PubMed2000

[A Lambert-Faton myasthenic syndrome and subacute cerebellar degeneration with a favorable clinical course after resection of small-cell lung cancer].

A case of Lambert-Eaton myasthenic syndrome (LEMS) and subacute cerebellar degeneration (SCD) was associated with small-cell lung cancer (SCLC). The patient, a 52-year-old man, who had noticed impotence one year previously, began to have ataxic gait, scanning speech and thirst progressing for 3 months, followed by weakness of the lower limbs, bilateral blepharoptosis, and double vision. Electromyographic studies showed low amplitude of compound muscle action potential (CMAP) and waxing phenomenon in high frequency stimulation of the ulnar nerve. A chest x-ray showed a mass lesion in the left hilar region, and small cell lung cancer was diagnosed on the basis of biopsy specimens. Anti-voltage-gated calcium channel (VGCC) antibody was positive. Anti-Yo and anti-Hu antibodies were negative. The patient was treated by lobectomy and chemotherapy, which resulted in improvement in the LEMS and SCD. Anti-VGCC antibody, the CMAP amplitude, and waxing phenomenon were improved. Operable cases of SCLC are rare. But we propose that anti-neoplastic treatment including resection of the tumor is the first choice for the treatment of paraneoplastic syndrome associated with SCLC.

Autoantibodies↗
PubMed1999

Anti-angiogenic activity of a novel synthetic agent, 9alpha-fluoromedroxyprogesterone acetate.

9Alpha-fluoromedroxyprogesterone acetate (FMPA) is a novel synthetic analog of medroxyprogesterone acetate (MPA), widely used as therapeutic agent for breast and endometrium cancers. FMPA showed almost the same binding affinities to the progesterone and glucocorticoid receptors as MPA. In the rabbit corneal assay, FMPA, MPA and fumagillin significantly inhibited the angiogenic response induced by rat mammary tumor at doses of 0. 1, 1 and 50 microg/pellet, respectively, so FMPA showed greater anti-angiogenic activity than MPA and fumagillin. In the mouse dorsal air sac method, FMPA inhibited the mouse sarcoma 180 cell-induced angiogenesis by oral administration at a dose of 200 mg/kg. FMPA inhibited the activity of plasminogen activator (PA) in bovine endothelial cells. These results suggest that FMPA may be useful for diseases associated with angiogenesis by oral administration.

Angiogenesis Inhibitors↗
PubMed1999

1,3-Disubstituted benzazepines as novel, potent, selective neuropeptide Y Y1 receptor antagonists.

A novel series of potent and selective non-peptide neuropeptide Y (NPY) Y1 receptor antagonists, having benzazepine nuclei, have been designed, synthesized, and evaluated for activity. Chemical modification of the R(1) and R(3) substituents in structure 1 (Chart 1) yields several compounds that show high affinity for the Y1 receptor (K(i) values of less than 10 nM). SAR studies revealed that introduction of an isopropylurea group at R(1) and a 3-(benzo-condensed-urea) group, 3-(fluorophenylurea) group, or a 3-(N-(4-hydroxyphenyl)guanidine) group at R(3) in structure 1 afforded potent and subtype-selective NPY Y1 receptor antagonists. 3-(3-(Benzothiazol-6-yl)ureido)-1-N-(3-(N'-(3-isopropylureido++ +))benzyl )-2,3,4,5-tetrahydro-1H-1-benzazepin-2-one (21), which was one of the most potent derivatives, competitively inhibited specific [(125)I]peptide YY (PYY) binding to Y1 receptors in human neuroblastoma SK-N-MC cells (K(i) = 5.1 nM). 21 not only inhibited the Y1 receptor-mediated increase in cytosolic free Ca(2+) concentration in SK-N-MC cells but also antagonized the Y1 receptor-mediated inhibitory effect of peptide YY on gastrin-induced histamine release in rat enterochromaffin-like cells. 21 showed no significant affinity in 17 receptor binding assays including Y2, Y4, and Y5 receptors.

Animals↗
PubMed1999

Positive selection of NKT cells by CD1(+), CD11c(+) non-lymphoid cells residing in the extrathymic organs.

Previously, we found that NK1.1(+), TCRalpha beta(+) natural killer T (NKT) cells develop in cytokine-supplemented suspension cultures of fetal liver established from normal, but not from beta2 microglobulin-deficient [beta2m(- / -)] mice, and that recombination-deficient SCID fetal liver can reconstiute NKT cell development in beta2m(- / -) fetal liver cultures. We found here that cells of SCID adult liver, bone marrow, spleen and thymus were able to reconstitute NKT cell development in the former culture system with efficiency comparable to normal thymic cells. The reconstitution of NKT cells was also seen in the bone marrow chimeras that had been administered a combination of beta2m(- / -) and Rag-2(- / -) bone marrow cells. Development of NKT cells was hampered by depletion of CD11c(+) or CD11b(+) cells, but not by removal of B220(+) or Gr-1(+) cells from cultures of normal fetal liver cells. Furthermore CD11c(+), CD11b(+) and / or CD11c(+) CD11b(-) cells (both populations were CD1-dull positive) enriched from Rag-2-deficient fetal livers and pulsed with alpha-galactosylceramide, a possible antigen for NKT cells, were shown to reconstitute the NKT cell development in beta2m(- / -) fetal liver cultures. Collectively, our findings suggest that non-lymphoid cells, presumably CD11c(+), CD11b(+) and / or CD11c(+), CD11b(-) dendritic cells, are involved in the mechanism of positive selection of NKT cells in the thymus and extrathymic organs.

Animals↗
PubMed1999

Genealogy of families of SINEs in cetaceans and artiodactyls: the presence of a huge superfamily of tRNA(Glu)-derived families of SINEs.

Several novel (sub)families of SINEs were isolated from the genomes of cetaceans and artiodactyls, and their sequences were determined. From comparisons of diagnostic nucleotides among the short interspersed repetitive elements (SINEs) in these (sub)families, we were able to draw the following conclusions. (1) After the divergence of the suborder Tylopoda (camels), the CHRS family of SINEs was newly created from tRNA(Glu) in a common ancestor of the lineages of the Suina (pigs and peccaries), Ruminantia (cows and deer), and Cetacea (whales and dolphins). (2) After divergence of the Suina lineage, the CHR-1 SINE and the CHR-2 SINE were generated successively in a common ancestor of ruminants, hippopotamuses, and cetaceans. (3) In the Ruminantia lineage, the Bov-tA SINE was generated by recombination between the CHR-2 SINE and Bov-A. (4) In the Suina lineage, the CHRS-S SINE was generated from the CHRS SINE. (5) In this latter lineage, the PRE-1 family of SINEs was created by insertion of part of the gene for tRNA(Arg) into the 5' region of the CHRS-S family. The distribution of a particular family of SINEs among species of artiodactyls and cetaceans confirmed the most recent conclusion for paraphyly of the order Artiodactyla. The present study also revealed that a newly created tRNA(Glu)-derived family of SINEs was subjected both to recombination with different units and to duplication of an internal sequence within a SINE unit to generate, during evolution, a huge superfamily of tRNA(Glu)-related families of SINEs that are now found in the genomes of artiodactyls and cetaceans.

Animals↗