Biomedical subjects
Publications and source records attributed to Hiroyuki Ishikawa.
The first enantioselective total synthesis of (-)-erinacine B has been achieved. Our approach features convergent construction of the 5-6-7 tricyclic cyathane core system via chiral building blocks prepared using asymmetric catalysis developed by us and highly stereoselective construction of all stereogenic centers in the aglycon. [reaction: see text].
OBJECTIVE: To investigate the effects of vibration (Vib) and hyaluronic acid (HA) on 3-dimensional cultured cartilage. METHODS: Chondrocytes were obtained from metatarsophalangeal joints of freshly killed 6-month-old pigs. Twenty-four-well plates containing type I collagen sponge disks were used to culture samples. The frequency and the amplitude of the vibration of the well plate were 100 Hz and 0.5 nm, respectively. We produced 3-dimensional cartilage tissue using HA and vibration with collagen sponge as a carrier. Four different culture conditions were examined: a control HA-Vib- group, an HA-Vib+ group, an HA+Vib- group, and an HA+Vib+ group. Each group was cultured for 2 weeks. After culture days 3, 7, 10, and 14 (every 3.5 days), the levels of chondroitin 4-sulfate (C4S) and chondroitin 6-sulfate (C6S) isomers synthesized in each culture medium were measured. Histologic analysis, immunohistochemical analysis, and electron microscopic examination were performed. RESULTS: Mean C4S and C6S synthesis had increased rapidly after 7 days of culture and continued to increase thereafter. There were significant differences among the 4 groups (P < 0.01). Synthesis of both C4S and C6S was most abundant in the HA+Vib+ group and the lowest in the HA-Vib- group. After 1 and 2 weeks of culture, the chondrocytes had formed stratified structures on the collagen sponges in all groups, although the thickest structure was observed in the HA+Vib+ group and the thinnest in the HA-Vib- group. Under immunofluorescence, the HA+Vib+ group exhibited the strongest chromatic features. Under electron microscopy, the chondrocytes in the HA+Vib+ group exhibited many long and slender prominences on their surface, and extracellular substance could be observed associated with the cells. CONCLUSION: Our results indicate that the combination of vibration and HA activates the production of proteoglycan in 3-dimensional cultured chondrocytes and stimulates MAPK and beta-catenin. This suggests that some mechanoreceptors for vibration exist on the plasma membrane of chondrocytes and activate the intracellular signal transduction system.
The rate of quinol oxidation by cytochrome bc(1)/b(6)f complex is in part associated with the redox potential (E(m)) of its Rieske [2Fe-2S] center, for which an approximate correlation with the number of hydrogen bonds to the cluster has been proposed. Here we report comparative resonance Raman (RR) characterization of bacterial and archaeal high-potential Rieske proteins and their site-directed variants with a modified hydrogen bond network around the cluster. Major differences among their RR spectra appear to be associated in part with the presence or absence of Tyr-156 (in the Rhodobacter sphaeroides numbering) near one of the Cys ligands to the cluster. Elimination of the hydrogen bond between the terminal cysteinyl sulfur ligand (S(t)) and Tyr-Oeta (as with the Y156W variant, which has a modified histidine N(epsilon) pK(a,ox)) induces a small structural bias of the geometry of the cluster and the surrounding protein in the normal coordinate system, and significantly affects some Fe-S(b/t) stretching vibrations. This is not observed in the case of the hydrogen bond between the bridging sulfide ligand (S(b)) and Ser-Ogamma, which is weak and/or unfavorably oriented for extensive coupling with the Fe-S(b/t) stretching vibrations.
This study was conducted to quantify the change in the number and size of myelinated nerve fibers of the maxillary nerve with tooth loss in humans. We carried out a morphometric analysis to compare the number and size of myelinated nerve fibers in the human maxillary nerve between four dentulous and four edentulous jaw cases. Our results indicated that the number of axons decreased by approximately 13,000 with tooth loss. The average size of axons remained unchanged, but there was a change in the fiber size distribution, namely the loss of a large number of small-sized axons was accompanied by the total disappearance of small number of large-sized axons.
Checkpoints, which monitor DNA damage and regulate cell cycle progression, ensure genomic integrity and prevent the propagation of transformed cells. DNA damage activates the p53-dependent checkpoint pathway that induces expression of p21Cip1/WAF1, resulting in cell cycle arrest at G1/S transition by inhibition of cdk activity and DNA replication. ICBP90 was identified as a nuclear protein that binds to the TopoII alpha gene promoter and is speculated to be involved in DNA replication. ICBP90 expression is cell cycle regulated in normal cells but stably high throughout cell cycle in various cancer cell lines. We here demonstrate that ICBP90 expression is down-regulated by the p53/p21Cip1/WAF1-dependent DNA damage checkpoint signals. The reduction of ICBP90 appeared to be caused by both transcriptional suppression and protein degradation. Adenoviral expression of p21Cip1/WAF1 directly led to ICBP90 reduction in p53-/- HCT116 cells without DNA damage. Furthermore, ICPB90 depletion by RNA interference significantly blocked G1/S transition after DNA damage in HeLa cells. The down-regulation of ICBP90 is an important mechanism for cell cycle arrest at G1/S transition, which is induced by the activation of a p53/p21Cip1/WAF1-dependent DNA-damage checkpoint. Deregulation of ICBP90 may impair the control of G1/S transition during checkpoint activation and lead to genomic instability.
The present work investigated the mechanism for down-regulation of thrombomodulin (TM), an anticoagulant glycoprotein, on cultured umbilical vein endothelial cells (HUVECs) exposed to lipid extracts from oxidized low-density lipoprotein (ox-LDL). HUVECs exposed to phospholipid extracts, but not to free cholesterol, triglyceride, or cholesterol ester, isolated from ox-LDL reduced TM mRNA levels to nearly the same extent as native ox-LDL. Oxidized 1-palmitoyl-2-arachidonyl-sn-glycero-3-phosphocholine (ox-PAPC), but not native PAPC or a reduced form of ox-PAPC, markedly decreased TM mRNA levels. The apparent half-life (t 1/2 = 2.7 hours) of TM mRNA in control cells was not significantly different from that in cells exposed to ox-LDL or ox-PAPC. TM mRNA levels were regulated by transcriptional activation via a retinoid receptor beta (RARbeta). The binding activities of nuclear proteins from HUVECs treated with ox-LDL or ox-PAPC to the DR4 or stimulatory protein 1 (Sp1) sequence in the TM promoter were significantly reduced with decreased expression of RARbeta, retinoid X receptor alpha (RXRalpha), Sp1, and Sp3 in the nuclei. The promoter activity in HUVECs transfected with a reporter plasmid expressing the TM promoter with targeted deletions in the DR4 and Sp1 binding elements was decreased to about 20% of that with the wild-type construct. Treatment of the cells with ox-PAPC had no additional effect on the promoter activity. These results suggest that oxidized phospholipids in ox-LDL inhibit transcription of the TM gene in HUVECs by inhibiting the binding of RARbeta-RXRalpha heterodimer and Sp, including Sp1 and Sp3, to the DR4 element and Sp1 binding element, respectively, in the TM promoter with reduced expression of RARbeta, RXRalpha, and Sp1 and Sp3 in the nuclei.
Paraneoplastic neurosyndrome (PNS) is a group of neurological disorders caused by or associated with neoplasms that are not direct effects of the primary tumor or of a metastasis to the involved organs. Chemotherapy, radiotherapy, immunosuppressive therapy, and plasmapheresis have been performed to treat PNS, but improvement of the neurological disorder is rather rare. A 64-year-old man was referred to our hospital with dysesthesia of the extremities and ataxic gait. Small cell lung cancer was diagnosed in another hospital and chemotherapy (CDDP 80 mg/m2 + VP-16 100 mg/m2) was performed. A partial response was obtained with this treatment, but the neurological dysfunction was exacerbated. Three months later, the patient was admitted to our hospital. On treatment with CDDP 80 mg/m2 (day 1) and CPT-11 80 mg/m2 (days 1, 8 and 15) and subsequent radiation therapy (60 Gy), his neurological disorder improved. We consider that neurological symptoms are important signs of malignancy in PNS and that a full course of treatment could improve the neurological disorders.
We report two cases of intramedullary spinal cord metastasis of lung cancer detected by MRI. Case 1: A 77-year-old man underwent chemotherapy and left lower lung lobectomy for squamous cell carcinoma of the lung (T2N0M0). About one year later, he complained of paresthesia of the lower extremities and claudication on walking, and then of weakness of the lower limbs and bladder dysfunction. Magnetic resonance imaging (MRI) revealed an enhanced mass in the dural sac at the level of the spines of L1-2. Volume reduction surgery was promptly performed. The pathological diagnosis was squamous cell carcinoma. Case 2: A small cell carcinoma of lung with metastasis to bone, kidney and cerebellum (T4 N3 M1) in a 73-year-old man was diagnosed. He showed a partial response to chemotherapies and to whole brain radiation (45 Gy). Three months later, he presented sudden onset paraplegia, paraesthesia and bladder dysfunction. MRI demonstrated an enhancing intramedullary lesion that delineated the conus of the cauda equina, and T 2-weighted MRI images showed multiple nodules in sacs.
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OBJECTIVE: To clarify the high-resolution CT(HRCT) findings of pulmonary atypical adenomatous hyperplasia (AAH) of 5 mm or less in diameter. MATERIALS AND METHODS: We evaluated the HRCT findings of 43 histopathologically confirmed AAH of 5 mm or less in diameter in 7 patients who underwent lobectomy for pulmonary adenocarcinoma. For comparison, we also examined the HRCT findings of 13 bronchioloalveolar carcinomas (BAC) of the same size from these patients. RESULTS: We identified 36 of 43 AAH and all 13 BAC on HRCT performed with multidetector-row CT. Thirty-five AAH and 11 BAC showed ground-glass opacity without any high-attenuation component. Margins of 20 AAH were well defined, and 16 were ill defined. In BAC, 11 lesions demonstrated well-defined margins, with only 2 showing ill-defined margins. CONCLUSION: Most AAH lesions of 5 mm or less in diameter are identified as ground-glass opacity on HRCT. Detection of minute ground-glass opacity is important in locating AAH on HRCT.
We investigated the roles of gamma delta T, NK, and NK1.1(+) T-like (NKT) cells in protective immunity against infection with Toxoplasma gondii. gamma delta T cells, NKT and NK cells, and NK cells in BALB/c mice were depleted by treatment with anti-TCR-gamma delta monoclonal antibody (mAb), anti-interleukin-2 receptor beta chain (IL-2R beta) mAb, and anti-asialoGM1 Ab, respectively, and these mice were infected with T. gondii. Treatment of mice with anti-TCR-gamma delta mAb aggravated toxoplasmosis, while treatment with anti-asialoGM1 Ab had no effects. Treatment with anti-IL-2R beta mAb enhanced the expression of heat shock protein 65 (HSP65) and gamma interferon (IFN-gamma) mRNA, while it inhibited interleukin-4 (IL-4) mRNA expression, ameliorating toxoplasmosis. In addition to NK cells, anti-IL-2R beta mAb eliminated cells expressing IL-2R beta and intermediate levels of CD3 (IL-2R beta(+) CD3(int)). Mice treated with anti-IL-2R beta mAb decreased the number of DX5(+) CD3(int) cells, which are considered to be equivalent to NK1.1(+)T cells in NK1.1 allele-negative strains. IL-2R beta(+) CD3(int) cells isolated from splenic and hepatic lymphoid cells were confirmed to express the TCR-V alpha 14 transcript. The magnitude of HSP65 induction in macrophages correlated with the protective potential against T. gondii infection after treatment with the antibodies, supporting our previous finding that gamma delta T cells play an essential role in the induction of HSP65 in host macrophages. Interestingly, NKT cells suppressed the expression of gamma delta T cell-induced HSP65 and IFN-gamma. Furthermore, depletion of IL-2R beta(+) CD3(int) cells suppressed the IL-4 mRNA expression. These results suggest that NKT cells may be the cells responsible for suppression of protective immunity against T. gondii infection by interfering with the gamma delta T cell-induced HSP65 expression, possibly through the generation of IL-4.
The aims of the present study were: (1) to investigate the statistical differences in jaw relationship assessments with the ANB angle and the Wits appraisal in Angle Class III children, and (2) to suggest guidelines for the use of these two parameters in this group of children. Seventy-five Angle Class I children with anterior crowding (male, 37; female, 38) and 96 Angle Class III children with anterior crossbite (male, 38; female, 58) were examined. All had undergone treatment that started at 8 or 9 years of age. Pre-treatment lateral cephalograms were used cross-sectionally for the analysis. The mean age was 8 years 7 months +/- 9 months in the Class I subjects, and 9 years 0 month +/- 7 months in the Class III subjects. To compare the assessments using ANB angle and the Wits appraisal in the Angle's Class III subjects, nine measured values from each individual subject were converted into Z scores in relation to the means and standard deviations of the two parameters in the Angle Class I subjects. The jaw discrepancy is assessed more severely using the ANB angle than by the Wits appraisal in these Angle Class III subjects. The paired t-test showed that the Z score of the ANB angle was significantly smaller than that of the Wits appraisal (P < 0.001). In Angle Class III subjects with a counter-clockwise mandibular rotation and a flattened occlusal plane, the ANB angle is a more critical cephalometric parameter than the Wits appraisal.
OBJECTIVE: This study examined the influence of two factors in the constriction of the maxillary dental arch by mucoperiosteal denudation of the palate: (1) inhibition of lateral growth and (2) medial inclination of teeth. METHOD: Thirty-five male 20-day-old Wistar rats were divided into experimental and control groups. The experimental group had bilateral mucoperiosteum excised in the lateral one third of the palate. Methyl methacrylate resin-embedded frontal sections were prepared from both groups after alternate weekly injections of tetracycline and calcein in the dorsal subcutaneous area. The sections were observed and photographed under either a confocal laser scanning microscope, a fluorescence microscope, or both. Chronological changes in lateral palatal growth, maxillary dental arch width, and inclination of the upper first molars were examined up to 8 weeks after the operation. Paraffin-embedded frontal sections were also made and stained with Elastica van Gieson stain. RESULTS: The scar tissue formed on the rat palate by the mucoperiosteal denudation was tightly connected to the palatal bone and teeth. The intervals between the labeling lines of the experimental group were less definite during the first 2 weeks after the operation. Increments of palatal and maxillary dental arch widths were smaller in the experimental group than in the control group. The upper first molars in the control group gradually inclined laterally, whereas those in the experimental group inclined medially with age. CONCLUSION: Medial inclination of teeth is a stronger influence than inhibition of lateral growth on constriction of the rat maxillary dental arch.
PURPOSE: To clarify the limitations of multidetector-row CT (MDCT) in detecting focal lung lesions of 5 mm or less in diameter by pathologic/high-resolution CT (HRCT) correlation. MATERIALS AND METHODS: Twenty-two patients who underwent both preoperative HRCT of the entire lobe using MDCT (MD-HRCT) and lobectomy for primary (n = 21) or metastatic (n = 1) lung tumor were studied. The author attempted to locate any focal lung lesions other than the main tumor throughout the resected and sliced specimens and to identify the opacities corresponding to the macroscopic lesions on MD-HRCT before histopathologic evaluation. Then two observers without pathologic information attempted to detect the lesions on MD-HRCT. RESULTS: Ninety-one lesions of 5 mm or less in diameter were found in 15 patients. Histopathologically, 13 lesions were classified as bronchioloalveolar carcinoma (BAC), 38 as atypical adenomatous hyperplasia (AAH), 9 as reactive hyperplasia (RH), 19 as inflammatory lesion (INF), 8 as solid lesion (SL), and 4 as showing no organizing change. The author, who had knowledge of the gross pathologic examinations, identified the opacities at rates of 100%, 82%, 56%, 42%, and 88% for BAC, AAH, RH, INF, and SL, respectively. The rates of lesion detection in the absence of knowledge of the pathologic examinations were 85%, 58%, 22%, 32%, and 75% for BAC, AAH, RH, INF, and SL, respectively. The rates of identification and detection of lesions more than 3 mm in diameter were 90% and 57%, respectively, while those of lesions less than 2 mm in diameter were 71% and 35%, respectively. CONCLUSIONS: MD-HRCT proved to be useful in detecting focal lung lesions of 5 mm or less in diameter; however, it is still difficult to detect lesions of less than 2 mm in diameter.
OBJECTIVE: To clarify the pathologic findings of ultrasmall pulmonary opacities (5 mm or smaller in diameter) found on multidetector-row high-resolution computed tomography (MD-HRCT). METHODS: Ten lobes in 10 patients were included in this study. Each lobe had a primary lung tumor and was removed surgically. Two thoracic radiologists noted any tiny nonlinear opacity on preoperative MD-HRCT films (1.25-mm thickness) covering the whole lobe. Pathologic findings of detected opacities were evaluated macroscopically and microscopically. RESULTS: Among 139 ultrasmall opacities 5 mm or smaller in diameter, 94 corresponded to normal anatomic structures (partial volume averaging or motion artifact), 36 corresponded to pathologic abnormalities, and 9 were unidentified. Histologic diagnoses of 36 pathologic abnormalities were inflammatory lesions (n = 16), intrapulmonary lymph nodes (IPLN; n = 7), atypical adenomatous hyperplasia (AAH; n = 7), bronchioloalveolar carcinoma (BAC; n = 5), and another neoplastic lesion (n = 1). CONCLUSION: Tiny pulmonary lesions, such as AAHs, BACs, and IPLNs, were identified among ultrasmall opacities found on MD-HRCT.