Biomedical subjects
Publications and source records attributed to M Hara.
Tetrocarcin A was recently identified as an inhibitor of the anti-apoptotic function of Bcl-2. We synthesized novel tetrocarcin derivatives in order to increase their selective inhibitory activity against Bcl-2. It was found that 21-acetoxy-9-glycosyloxy derivatives had potent Bcl-2 inhibitory activity without significant antimicrobial activity.
We present evidence that donor-reactive CD4(+) T cells present in mice tolerant to donor alloantigens are phenotypically and functionally heterogeneous. CD4(+) T cells contained within the CD45RB(high) fraction remained capable of mediating graft rejection when transferred to donor alloantigen-grafted T cell-depleted mice. In contrast, the CD45RB(low) CD4(+) and CD25(+)CD4(+) populations failed to induce rejection, but rather, were able to inhibit rejection initiated by naive CD45RB(high) CD4(+) T cells. Analysis of the mechanism of immunoregulation transferred by CD45RB(low) CD4(+) T cells in vivo revealed that it was donor Ag specific and could be inhibited by neutralizing Abs reactive with IL-10, but not IL-4. CD45RB(low) CD4(+) T cells from tolerant mice were also immune suppressive in vitro, as coculture of these cells with naive CD45RB(high) CD4(+) T cells inhibited proliferation and Th1 cytokine production in response to donor alloantigens presented via the indirect pathway. These results demonstrate that alloantigen-specific regulatory T cells contained within the CD45RB(low) CD4(+) T cell population are responsible for the maintenance of tolerance to donor alloantigens in vivo and require IL-10 for functional activity.
Although it is widely accepted that there is a hierarchy in the susceptibility of different allografts to rejection, the mechanisms responsible are unknown. We show that the increased susceptibility of H-2K(b+) skin and islet allografts to rejection is not based on their ability to activate more H-2K(b)-specific T cells in vivo; heart allografts stimulate the activation and proliferation of many more H-2K(b)-specific T cells than either skin or islet allografts. Rejection of all three types of graft generate memory cells by 25 days posttransplant. These data provide evidence that neither tissue-specific Ags nor, surprisingly, the number of APCs carried in the graft dictate their susceptibility to T cell-mediated rejection and suggest that the graft microenvironment and size may play a more important role in determining the susceptibility of an allograft to rejection and resistance to tolerance induction.
A method for analyzing the tissue distribution of myrosinase activity in Brassicaceous plants was developed. This technique is based on 'tissue printing' to visualize enzyme activity. The freshly-cut surface (transverse direction) of the root of three species, Japanese radish (Raphanus sativus), turnip (Brassica campestris) and Japanese horseradish (wasabi, Wasabia japonica), was pressed onto a polyvinylidene difluoride (PVDF) filter to immobilize the proteins onto the membrane. The sites of myrosinase activity on the membranes were visualized by the sinigrin-glucose oxidase-peroxidase system. Signals for myrosinase activity were observed in both the epidermis and vascular cambium of the root of the Japanese radish, turnip and wasabi. Measurement of myrosinase activity in protein extracts indicated that the level of myrosinase activity in the peeling, which consisted of the epidermis, cortex and vascular cambium, was much higher than that in the peeled root of the three species. These results support the image that myrosinase activity, obtained in tissue printing, corresponded well with the tissue distribution of myrosinase activity.
Sepiapterin reductase (EC 1.1.1.153; SPR) is an enzyme involved in the biosynthesis of tetrahydrobiopterin; and SPR has been identified as a member of the NADP(H)-preferring short-chain dehydrogenase/reductase (SDR) family based on its catalytic properties for exogenous carbonyl compounds and molecular structure. To examine possible differences in the catalytic sites of SPR for exogenous carbonyl compounds and the native pteridine substrates, we investigated by site-directed mutagenesis the role of the highly conserved Ser-Tyr-Lys triad (Ser and YXXXK motif) in SPR, which was shown to be the catalytic site of SDR-family enzymes. From the analysis of catalytic constants for single- and double-point mutants against the triad, Ser and YXXXK motif, in the SPR molecule, participate in the reduction of the carbonyl group of both pteridine and exogenous carbonyl compounds. The Ser and the Tyr of the triad may co-act in proton transfer and stabilization for the carbonyl group of substrates, as was demonstrated for those in the SDR family. But either the Tyr or the Ser of SPR can function alone for proton transfer to a certain extent and show low activity for both substrates.
Dilated cardiomyopathy is a severe pathology of the heart with poorly understood etiology. Disruption of the gene encoding the negative immunoregulatory receptor PD-1 in BALB/c mice, but not in BALB/c RAG-2-/- mice, caused dilated cardiomyopathy with severely impaired contraction and sudden death by congestive heart failure. Affected hearts showed diffuse deposition of immunoglobulin G (IgG) on the surface of cardiomyocytes. All of the affected PD-1-/- mice exhibited high-titer circulating IgG autoantibodies reactive to a 33-kilodalton protein expressed specifically on the surface of cardiomyocytes. These results indicate that PD-1 may be an important factor contributing to the prevention of autoimmune diseases.
Explore the source record for details and available documents.
The tumor suppressor p16/CDKN2A/INK4a gene is frequently mutated, mostly by homozygous deletions in high-grade gliomas. Although the p16 protein suppresses cell proliferation primarily through inhibition of cell-cycle progression at the G1 phase, other phenotypic changes in glioma cells associated with p16INK4a alterations have not been fully described. To determine the roles of p16 alterations in glioma formation, we have established ecdysone-driven inducible p16 expression in the human glioblastoma cell line CL-4, which were derived from p16-null U87MG cells. Here we show that exogenous p16 expression in CL-4 cells results in morphological changes, with large and flattened cytoplasm, which are associated with increased formation of cytoplasmic actin-stress fibers and vinculin accumulation in the focal adhesion contacts. Adhesion of CL-4 cells to extracellular matrix proteins, such as laminin, fibronectin, and type IV collagen, significantly increased upon exogenous p16 expression, which correlated with increased expression of integrin alpha5 and alphav. Expression of a small GTP-binding protein, Rac, also decreased. Following epidermal growth factor stimulation, phosphorylation of MAP kinases ERK1 and 2 and induction of an early immediate gene product, c-Fos, were significantly reduced in CL-4 cells with p16 expression. These results suggest that the tumor suppressor p16 may exert its antitumor effects through modulation of multiple aspects of glioblastoma phenotypes, including proliferation, invasiveness, and responsiveness to extracellular growth stimuli.
Bacillus thuringiensis was recovered at a high frequency from activated-sludge system environments in an urban sewage-digestive plant. All of the test materials, sampled at several digesting steps, contained the organism. Of 515 colonies belonging to the B. cereus/B. thuringiensis group, 45 (8.7%) were assigned to B. thuringiensis. The highest density of this bacterium was 1.6 x 103 cfu/ml in a scum sample of the first aeration basin. Among the 45 isolates, 7 were assigned to the known H serovars. Two isolates of the serovar kenyae isolates exhibited Lepidoptera-specific toxicity. Diptera-specific toxicity was shown by an isolate of serovar israelensis and a serologically undefined isolate. Lectin activity was associated with 12 isolates.
We recently examined the clinicopathological and immunohistochemical features of four cases of primary hepatic carcinoma with sarcomatoid elements. Three of the four patients had associated ordinary hepatocellular carcinoma (HCC) and one had a sarcomatoid carcinoma with no apparent elements of HCC. The presenting symptoms were high fever and hypochondralgia in three patients, and right hypochondralgia without a high fever in one. The preoperative diagnoses were liver abscess in two patients, HCC in one, and cholangioma in one. Preoperative imaging showed necrotic change or abscess formation in the tumors. The sarcomatous elements showed a positive reaction to vimentin in three patients, but the ordinary HCC cells did not. Macroscopically, the tumors appeared as a single nodule with pericapsular growth. The prognoses of these patients were poor due to the early development of intrahepatic or distal metastases. We conclude that symptoms such as a high fever or hypochondralgia are characteristics of these tumors and that they may be histogenetically derived from a dedifferentiation of HCC, although no elements of HCC were found in one of our cases.
We report herein the case of a 42-year-old woman in whom a pancreatic carcinoma was found 17 years after excision of a choledochal cyst with Roux-en-Y hepaticojejunostomy. Although the incidence of biliary carcinoma associated with choledochal cyst is high, reports of cancer developing in the remaining intrapancreatic biliary tract or pancreas in patients who have previously undergone primary excision of a choledochal cyst are extremely rare. Long-term follow-up is recommended even for patients who have undergone excisional surgery for a choledochal cyst, in consideration of the possibility that cancer associated with the intrapancreatic biliary tract or pancreas may develop.
A 65-year-old man was referred to our hospital for treatment of a liver tumor. Abdominal ultrasonography (US) demonstrated a low echoic mass in the S2-S4 region of the liver, which was confirmed by abdominal computed tomography (CT). In the delayed phase of angio-CT, the inside of the mass was not enhanced. Abdominal angiography showed a hypovascular area in the liver. An extended left lobectomy was performed. Macroscopically, the tumor was 9.5 x 9.5 cm in size, and on cross section, it was white and clearly demarcated from the surrounding tissue. Microscopic observation of hematoxylin-eosin-stained specimens did not show any glandular or trabecular formation. Histologically, there was diffuse proliferation of atypical spindle cells that had hyperchromatic, short, spindle-shaped nuclei, and pale cytoplasm with poor intercellular adhesion. The nontumorous tissue was almost normal with no sign of cirrhosis. Immunohistochemical examination showed that the spindle cells were positive for vimentin and cytokeratins (AE1/AE3, CAM 5.2), but negative for all other markers. The final diagnosis was a sarcomatoid carcinoma, the origin of which was not able to be confirmed immunohistochemically. This case of a primary hepatic tumor composed of malignant cells with sarcomatous features is described, and the immunohistochemical findings are discussed.
BACKGROUND: The effect of adrenomedullin, a vasodilatory peptide on transient middle cerebral artery (MCA) occlusion was investigated in rats. METHODS: Transient MCA occlusion for 2 hours was made by using the intra-arterial suture method, followed by reperfusion. FINDINGS: An intravenous infusion of adrenomedullin (1 microg/kg/min) from one hour before ischemia to one hour after ischemia significantly reduced the infarct size and improved neurological deficits (p<0.05), without affecting systemic blood pressure or other physiological parameters. The infarct size was reduced with adrenomedullin by 25.4+/-12.7%, 31.3+/-5.8%, 31.6+/-6.1% respectively at the coronal level 6, 8 and 10 mm posterior from the frontal pole. Adrenomedullin also significantly inhibited the increase in myeloperoxidase (MPO) activity in the MCA area of the ischemic hemisphere after 22-hour reperfusion (control: 0.205+/-0.054 unit/g wet tissue, adrenomedullin group: 0.047+/-0.009 unit/g wet tissue, p<0.0001). INTERPRETATION: These data suggest that adrenomedullin reduces acute ischemic brain injury and one of is neuroprotective mechanisms may be derived from inhibition of the infiltration of neutrophils into the ischemic tissue.
Adenoid cystic carcinoma (ACC) is a relatively common head and neck tumor which grows slowly but locally aggressive and prone to recurrence. ACC most commonly arises in the major and minor salivary glands. Some rare cases of intracranial ACC with an unknown primary site have been reported. The authors present the first case of primary intracranial ACC of the suprasellar region. A 34 year-old female presented with one month's duration of visual disturbance and galactorrhea. Magnetic resonance image (MRI) showed intra- and suprasellar mass mimicking a craniopharyngioma. There was no evidence of invasion from an extracranial site. The operative findings showed the mass existed under the arachnoid membrane and seemed to originate from the pituitary stalk. Pathological diagnosis was ACC. After the first operation, local recurrence and CSF dissemination to the lower clivus occurred within two months. Recurrence repeatedly treated by Gamma knife radiosurgery 10 times and 4 times by surgery during a 3 year follow-up period. But total removal of the tumor at the first operation along with radiosurgery may control the lesion and prevent further recurrence.
We screened the protein-coding region of the peroxisome proliferator-activated receptor alpha gene (PPARA) and the flanking intron sequences for mutations in 57 unrelated Japanese subjects with maturity-onset diabetes of the young (MODY). We found three missense mutations, designated P22R, D140Y, and V227A. The D140Y and V227A mutations were found at similar frequencies in MODY and in nondiabetic Japanese subjects, suggesting that they were unlikely to be pathogenic. The P22R mutation was found in a single female subject with MODY. Two of her four siblings, all of whom were diagnosed with diabetes before age 35 years, also inherited the P22R mutation. However, two other diabetic siblings had not inherited the mutant allele, implying that the P22R mutation was not the cause of MODY in this family. Variation in the coding region of PPARA is unlikely to be a major cause of MODY in Japanese people.
Allele segregating patterns of microsatellite DNA loci in 5 experimental families of Japanese flounder Paralichthys olivaceus and genotype frequencies for deviation from Hardy-Weinberg expectations (HWE) in natural P. olivaceus populations were studied to assess inheritability. Of the 12 microsatellite loci examined, 1 locus had a possibility of scoring errors of heterozygous individuals caused by unreproducible polymerase chain reaction amplifications of a particular allele. At the remaining 11 loci, almost all of alleles were segregated according to Mendelian transmission, and observed genotype frequencies in natural populations were consistent with HWE. The results demonstrated here would provide useful information supporting the suitability of these microsatellite loci as inheritable P. olivaceus genetic markers.
We examined population genetic structure by means of microsatellite analysis among 7 Japanese flounder (Paralichthys olivaceus) populations collected from coastal sea areas around Japan. As was expected, all of the 11 microsatellite loci examined were variable in all populations (number of alleles per locus, 15.2-18.2; average of expected heterozygosity, 0.74-0.78). Eleven population pairs in 21 possible pairwise comparisons showed significant genetic heterogeneity associated with allele frequency distributions or fixation index (F(ST)). Modified Cavalli-Sforza chord distance (D(A)) and Nei's standard genetic distance (D(ST)) ranged from 0.051 to 0.090, and from 0.000 to 0.025, respectively. There was evidence that the populations assessed in this study were not drawn from a single panmictic population; however, it appears that Japanese flounder populations around Japan are not well-structured, as an estimate of the fixation index value among the 7 localities was very low (F(ST) = 0.0025).
Population differentiation and relationships among 6 natural rockfish populations collected from northern coastal seas around Japan were assayed using microsatellite DNA loci. Seven loci examined were polymorphic in all populations. The number of alleles per locus ranged from 6.7 to 9.3, and the average of observed and expected heterozygosity ranged from 0.63 to 0.68, and from 0.66 to 0.69, respectively. The observed genotype frequencies at each locus were almost in agreement with Hardy-Weinberg expectations with two exceptions (P <.05). The allele frequencies of 16 population pairs were significantly different (P <.05). Genetic distance (D(A)) between 6 populations ranged from 0.03 to 0.08. According to a neighbor-joining tree generated from the D(A) values, the 6 populations fell into 3 clusters. These clusters were correlated with the geographical positions of each population; larval dispersions due to water current were also found to have an effect on these results.