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Biomedical subjects

H Fujii

Publications and source records attributed to H Fujii.

At least 433 records · Page 24Linked to original sources
PubMed1996

Effect of bile on the intestinal bile-acid binding protein (I-BABP) expression. In vitro and in vivo studies.

Enterocytes actively transport bile acids from the ileal lumen to the portal blood. This physiological process greatly contributes to maintaining the bile acid homeostasis. However, little is known about the molecular mechanisms involved in this transport system. The effect of bile on gene expression of the intestinal bile-acid binding protein (I-BABP) expressed in the enterocytes was studied in vivo, using the by-pass method, and in vitro, using organ culture of ileum explants and Caco-2 cell line. The low cytosolic I-BABP concentration and I-BABP mRNA level found in diverted ileum was totally recovered when bile was added in the ileal lumen. Northern blot analysis of the ileal explants revealed a dose-dependent increase in the I-BABP mRNA in the presence of bile. In Caco-2 cells, the I-BABP transcript was dramatically increased in the presence of human bile while it was undetectable in the control cultures. These data offer the first evidence that biliary components regulate the I-BABP gene expressed in the enterocytes.

Animals↗
PubMed1996

Vaccination of tumor cells transfected with the B7-1 (CD80) gene induces the anti-metastatic effect and tumor immunity in mice.

The present study demonstrates that the transfection of B7-1 or its variant MB7-2 genes into MHC class I+ tumor cells (B16-BL6 or K1735-M2 melanoma) resulted in the remarkable reduction of lung metastasis caused by i.v. injection into immunocompetent syngeneic mice. However, i.v. injection of the transfectants into T cell-deficient nude mice did not affect reduction of lung tumor colonies as compared with parental wild-type tumors, suggesting that such an inhibitory effect was closely associated with T cell-mediated responses. The reduced metastasis of B7+ tumor cells consequently led to the significant prolongation of survival. Expression of B7 on tumor cells did not influence the tumorigenicity in vivo and tumor cell invasion into basement membrane Matrigel in vitro. We also found that immunization of X-irradiated B7 transfectants was effective as a tumor vaccine for preventing lung metastasis caused by i.v. injection of B7- parental B16-BL6 cells but not against other syngeneic 3LL tumors. Thus, the B7-mediated anti-metastatic effect was tumor-specific. Vaccinations of irradiated B7+ tumor cells before and after surgical excision of the s.c. inoculated primary B7- tumors on day 21 achieved effectively the prevention of spontaneous lung metastasis. Our report that vaccination of irradiated B7+ tumor cells led to a therapeutic effect in an established tumor metastasis model clearly expands and confirms previous related observations.

Animals↗
PubMed1996

Genetic divergence in the clonal evolution of breast cancer.

The progression of ductal carcinoma in situ (DCIS) to infiltrating and metastatic cancer of the breast is thought to be a consequence of clonal expansions of neoplastic cells with progressively more genetic alterations. To study this progression, we first dissected multiple foci from each of 23 breast tumors with DCIS only and 20 cases with synchronous DCIS and infiltrating cancer. We than tested microsatellite markers by PCR for allelic losses in the individual foci for loci on chromosomes 6q, 9p, 11q, 13q, 16q, 17q, and 17p. The patterns of allelic losses identified in the in situ cancers were generally conserved in the synchronous infiltrating tumors, supporting the paradigm that the infiltrating tumors are clonally derived from the in situ lesions. However, in 8 (40%) of the 20 cases with synchronous in situ and invasive cancer, heterogeneous patterns of allelic loss at one or more chromosomal loci were observed in adjacent DCIS foci. Moreover, some of the allelic losses recognized in in situ portions of the tumors were not conserved in the clonal progression to the synchronous invasive tumor. Such allelic loss heterogeneity was noted in only 1 of the 20 infiltrating tumors and only 3 of the 23 cases of DCIS without invasion that were studied in a similar manner. This heterogeneity indicated genetic divergence during the clonal evolution of breast cancer, particularly at the time when in situ cancers progress to invasive cancers.

Breast Neoplasms↗
PubMed1996

Oxygen and one reducing equivalent are both required for the conversion of alpha-hydroxyhemin to verdoheme in heme oxygenase.

Heme oxygenase is a central enzyme of heme degradation and associated carbon monoxide biosynthesis. We have prepared the alpha-hydroxyheme-heme oxygenase complex, which is the first intermediate in the catalytic reaction. The active site structure of the complex was examined by optical absorption, EPR, and resonance Raman spectroscopies. In the ferric form of the enzyme complex, the heme iron is five coordinate high spin and the alpha-hydroxyheme group in the complex assumes a structure of an oxophlorin where the alpha-meso hydroxy group is deprotonated. In the ferrous form, the alpha-hydroxy group is protonated and consequently the prosthetic group assumes a porphyrin structure. The alpha-hydroxyheme group undergoes a redox-linked conversion between a keto and an enol form. The ferric alpha-hydroxyheme reacts with molecular oxygen to form a radical species. Reaction of the radical species with a reducing equivalent yields the verdoheme-heme oxygenase complex. Reaction of the ferrous alpha-hydroxyheme-heme oxygenase complex with oxygen also yields the verdoheme-enzyme complex. We conclude that the catalytic conversion of ferric alpha-hydroxyheme to verdoheme by heme oxygenase requires molecular oxygen and one reducing equivalent.

Animals↗
PubMed1996

Functional role of sialyl Lewis X and fibronectin-derived RGDS peptide analogue on tumor-cell arrest in lungs followed by extravasation.

Our study demonstrates that synthetic sialyl Lewis X (SLex) as a ligand for selectins and fibronectin-derived RGDS peptide analogue [Ar(DRGDS)3] inhibits lung metastases produced by i.v. co-injection of B16-BL6 melanoma cells. To investigate the inhibitory mechanisms in a living animal, we performed positron-emission tomography (PET) analysis after i.v. injection of [2-18F]2-fluoro-2v-deoxy-D-glucose-labeled tumor cells with or without liposomal SLex or Ar(DRGDS)3. The real-time PET measurement for the first 120 min, started immediately after injection, showed that tumor-cell arrest, i.e., accumulation in the target organ (lung) was remarkably inhibited by liposomal SLex, but not inhibited by Ar(DRGDS)3 or liposomal Me-SLex, which is not recognized by selectins. In contrast, Ar(DRGDS)3 inhibited the invasion of B16-BL6 cells into reconstituted basement membrane (Matrigel) following tumor arrest, whereas SLex- or Me-SLex-entrapped liposomes did not affect tumor invasion. In the metastatic processes containing tumor-cell lodgement and arrest in the target organ followed by extravasation (invasion), SLex resulted in the inhibition of initial arrest of tumor cells, presumably tumor-endothelium interaction, while Ar(DRGDS)3 achieved inhibition of tumor invasion into basement membrane at later steps of the cascade, consequently leading to inhibition of metastasis. Thus, tumor-cell arrest in lungs in the metastatic processes must be precisely and properly controlled by different adhesion molecules at different stages, which are similar to those observed in leukocyte-endothelium interaction.

Amino Acid Sequence↗
PubMed1996

Three cases of hereditary nonspherocytic hemolytic anemia associated with red blood cell glutathione deficiency.

Three unrelated Japanese patients with chronic nonspherocytic hemolytic anemia wer found to have marked deficiency of red blood cell (RBC) reduced glutathoine (GSH) (4.4%, 13.1%, and 6.9% of normal, respectively). A panel of RBC enzyme assays showed that one patient had decreased glutathione synthetase activity and the other two were moderately deficient in gamma-glutamylcystine synthetase. Some family members of each patient showed mild deficiency of the respective enzymes. RBCs of these patients also showed a decreased level of glutathione-S-transferase as in previously described GSH-deficient cases. Hemolytic anemia was their only manifestation, and neither 5-oxoprolinemia nor 5-oxoprolinuria, which are usually associated with to generalized type of glutathione synthetase deficiency, was noted in our patients.

Adolescent↗
PubMed1996

cDNA cloning of a murine homologue of Drosophila single-minded, its mRNA expression in mouse development, and chromosome localization.

A combination of the RT-PCR method and subsequent screening of the cDNA library of mouse skeletal muscle with the cDNA isolated by RT-PCR used as a probe led to isolation of cDNAs encoding a polypeptide (mSim) with bHLH and PAS domains which show high similarity to the corresponding regions of Drosophila Sim, a master regulator in neurogenesis. Experiments using a GST-fusion protein demonstrated that mSim heterodimerizes with Arnt (Ah receptor nuclear translocator), even more efficiently than AhR (Ah receptor) does with Arnt. RNA blot analysis using RNAs from various tissues of mice indicated that mSim transcript is expressed in several limited tissues such as muscle, kidney and lung of adult animals. Distribution of mSim mRNA was always accompanied with that of Arnt. All the results suggest a regulatory role of mSim in partnership with Arnt. Chromosomal location of the mSim gene was determined by fluorescent in situ hybridization to be localized on the C3.3-C4 band of mouse chromosome 16 which is syntenic with the human chromosome 21q22 carrying the Down syndrome critical region, where a gene highly homologous to the Drosophila sim was localized. Whole mount in situ hybridization using a unique part of mSim cDNA sequence showed that mSim mRNA was expressed in the ventral diencephalon, branchial arches and limbs. These findings will provide an approach to the cause of the Down syndrome as well as the elucidation of the functional roles of mSim in animal development.

Age Factors↗
PubMed1996

Molecular basis of erythroenzymopathies associated with hereditary hemolytic anemia: tabulation of mutant enzymes.

Molecular abnormalities of erythroenzymopathies associated with hereditary hemolytic anemia have been determined by means of molecular biology. Pyruvate kinase (PK) deficiency is the most common and well-characterized enzyme deficiency in the glycolytic pathway, and it causes hereditary hemolytic anemia. To date, 47 gene mutations have been identified. We identified one base deletion, one splicing mutation, and six distinct missense mutations in 12 unrelated families with a homozygous PK deficiency. Mutations located near the substrate or fructose-1,6- diphosphate binding site may change the conformation of the active site, resulting in a drastic loss of activity and severe clinical symptoms. Glucose-6-phosphate dehydrogenase (G6PD)deficiency is the most common metabolic disorder, and it is associated with chronic hemolytic anemia and/or drug- or infection-induced acute hemolytic attack. An estimated 400 million people are affected worldwide. The mutations responsible for about 78 variants have been determined. Some have polymorphic frequencies in different populations. Most variants are produced by one or two nucleotide substitutions. Molecular studies have disclosed that most of the class 1 G6PD variants associated with chronic hemolysis have the mutations surrounding either the substrate or the NADP binding site. Among rare enzymopathies, missense mutations have been determined in deficiencies of glucosephosphate isomerase, (TPI), phosphoglycerate kinase, and adenylate kinase. Compound heterozygosity with missense mutation and base deletion has been determined in deficiencies of hexokinase and diphosphoglyceromutase. Compound heterozygosity with missense and nonsense mutations has been identified in TPI deficiency. One base junction mutations resulting in abnormally spliced PFK-M mRNA have been identified in homozygous PFK deficiency. An exception is hemolytic anemia due to increased adenosine deaminase activity. The basic abnormality appears to result from the overproduction of a structurally normal enzyme.

Anemia, Hemolytic↗
PubMed1996

Detection of frequent allelic loss of 6q23-q25.2 in microdissected human breast cancer tissues.

Detection of allelic loss in human breast cancer is hindered by the fact that breast cancer tissues are frequently infiltrated by stromal and inflammatory cells. For this study, we carefully microdissected infiltrating breast cancer tumor cells from contaminating normal cells and analyzed the DNA from these samples for allelic loss on the long arm of chromosome 6 by using a panel of 15 dinucleotide repeat markers. We found 53 of the 66 cases studied (80%) to have allelic loss of either the entire chromosomal arm (37 cases) or a portion of the chromosomal arm (16 cases). One common region that was identified for all tumors with deletions of 6q was the area between markers D6S310/314 and D6S473/255, consistent with a tumor suppressor gene locus at 6q23-6q25.2. The use of tissue microdissection allowed the detection of allelic loss in this chromosomal region in human breast cancer at a much higher frequency than was previously recognized.

Adult↗
PubMed1996

Autopsy case of colocalized tumors of hepatocellular carcinoma and malignant lymphoma.

We present a rare case of colocalized tumors of hepatocellular carcinoma (HCC) and malignant lymphoma in the liver and bone marrow. A 64-year-old man with hepatitis B virus (HBV)-induced cirrhosis was admitted after detection of elevated serum alpha-fetoprotein level. He was diagnosed as having HCC and treated with chemotherapy and radiotherapy, but the size of the tumors did not diminish. After 11 months' hospitalization, he died due to rupture of esophageal varices. Autopsy revealed two heterogenic malignant tumors, HCC and malignant lymphoma (B cell type), in the liver. These tumors showed colocalization in the liver and bone marrow. The carcinogenetic process of colocalized tumors of HCC and lymphoma was not clarified, but the possibility that persistent HBV infection play a role in promoting hepatocarcinogenic and hematopoietic tumor growths in the reticuloendothelial organs could not be excluded.

Autopsy↗
PubMed1996

Expression of cutaneous fatty acid-binding protein and its mRNA in rat skin.

Cutaneous fatty acid-binding protein (C-FABP) has been purified from rat skin. Since there was little information about the role of C-FABP in the skin, we investigated the expression of C-FABP and its mRNA in normal rat skin using an immunohistochemical technique and in situ hybridization. In the epidermis, C-FABP mRNA was found to be expressed in basal cells and highly in prickle cells, while C-FABP itself was strongly expressed in the upper prickle and the granular cell layers. In sebaceous glands, both C-FABP and its mRNA were expressed in both peripheral and differentiating cells, although the expression of C-FABP mRNA gradually reduced during differentiation of sebocytes. Since epidermis and sebaceous glands are active sites of fatty acid synthesis, these results suggest that C-FABP may have important roles in the transport and synthesis of fatty acids.

Animals↗
PubMed1996

Usefulness of Ga-67 brain SPECT in patients with CNS malignant lymphoma.

The efficacy of Ga-67 SPECT imaging of CNS malignant lymphoma was investigated in 14 studies of 11 patients. As compared with planar images, the SPECT imaging improved the detectability of the focus of CNS malignant lymphoma. All untreated cases showed L/N ratios higher than 3.0. And the L/N ratios also changed according to remission or relapse of CNS malignant lymphoma.

Adult↗
PubMed1996

Abnormal excitability of the corticospinal pathway in patients with amyotrophic lateral sclerosis: a single motor unit study using transcranial magnetic stimulation.

The pathophysiology of corticospinal tract degeneration in amyotrophic lateral sclerosis (ALS) was investigated by studying the effect of transcranial magnetic stimulation on discharge characteristics of single motor units during voluntary activation. The motor units were recorded from the first dorsal interosseus muscles of 12 patients with ALS, 14 healthy subjects, 12 patients with upper motor neuron lesions and 9 with pure lower motor neuron diseases. More than 100 magnetic stimuli were delivered over the scalp during minimal muscle contraction. The occurrence of motor unit discharges was plotted in a peristimulus time histogram. An increase in discharge probability at latencies of 20-30 msec, that represents monosynaptic activation (primary peak) was found in normal units. Motor units from ALS patients with short disease durations had significantly increased discharge probabilities in the primary peak (P < 0.001). Motor units from 4 ALS patients with upper motor neuron signs showed double primary peaks: an initial synchronized peak followed by a dispersed peak. The latter was ascribed to a slow corticospinal pathway, which remains undetected or is functionally insignificant in healthy subjects. We conclude that the excitabilities of the surviving corticospinal tract pathways are abnormally increased in ALS, especially in the early stage.

Adolescent↗
PubMed1996

Diffuse disorder of coronary artery vasomotility in patients with coronary spastic angina. Hyperreactivity to the constrictor effects of acetylcholine and the dilator effects of nitroglycerin.

OBJECTIVES: We examined the vasomotility of the entire epicardial coronary artery system in patients with and without coronary spastic angina. BACKGROUND: The coronary arteries of patients with variant angina are hyperreactive to diverse constrictor stimuli. It is unclear whether the abnormal responses to constrictive or dilative stimuli, or both, result from a localized or diffuse disorder in the coronary artery tree. METHODS: Coronary artery diameter responses to intracoronary acetylcholine and nitroglycerin were examined at the proximal, middle and distal segments of three principal coronary arteries in 36 patients with coronary spastic angina without significant stenosis and in 12 young (< or = 30 years old) and 20 older control subjects (> 30 years old) with normal coronary arteriographic findings. In 10 patients with significant coronary stenosis, the responses of the prestenotic segments were also examined. RESULTS: In patients with coronary spastic angina, coronary spasm was induced in 23 left anterior descending, 13 left circumflex and 17 right coronary arteries by acetylcholine. Multivessel spasm was observed in 15 patients. Acetylcholine had a dilator effect on most segments in young control subjects and a mild constrictor effect in older control subjects and in patients with significant stenosis. Comparison of the responses to acetylcholine among groups demonstrated that the constrictor response of the artery with spasm was enhanced significantly and diffusely. That of the artery without spasm also tended to be enhanced. Coronary artery diameters after nitroglycerin did not differ in any segment among patients with coronary spastic angina and both control groups. In patients with coronary spastic angina, nitroglycerin significantly enhanced dilation in all segments of the artery with spasm compared with that observed in both control groups and in most segments of the artery without spasm. Patients with significant coronary stenosis had a reduced response compared with that in control subjects. CONCLUSIONS: Hyperreactive responses not only to the constrictor effects of acetylcholine, but also the dilator effects of nitroglycerin were detected diffusely in the epicardial coronary arteries of patients with coronary spastic angina. This finding indicates that a diffuse, not localized, disorder in vasomotility is involved in the pathogenesis of coronary spastic angina.

Acetylcholine↗
PubMed1996

Identification of putative downstream genes of Oct-3, a pluripotent cell-specific transcription factor.

BACKGROUND: Oct-3, a pluripotent cell-specific POU transcription factor, appears to be a key regulator in pluripotential early embryonic cells and germ cells. In order to study how pluripotency is maintained, it is essential to know what genes are regulated by Oct-3. RESULTS: By employing a subtraction method, we identified several pluripotent cell-specific genes. Based upon expression patterns in various cell lines lacking or possessing Oct-3 function, about half of the genes were placed downstream of Oct-3. These downstream genes included a previously-known gene (Glut-3: a gene for a glucose transporter) and novel genes (226, 383 and 880). Their expression patterns paralleled that of Oct-3: all of these genes were highly expressed in pluripotent cells such as EC/ES cells, but switched off upon differentiation. More importantly, their expression was rescued in 'revertant' cells that ectopically acquired the Oct-3 transactivating function. Furthermore, the expression profiles of Glut-3, 226 and 383 during mouse development also overlapped that of Oct-3. The Glut-3 gene possessed multiple Oct-3 binding sites in its transcriptional regulatory regions, suggesting that at least one of the downstream genes was a direct target of Oct-3. CONCLUSIONS: A large proportion of pluripotent cell-specific genes appear to be downstream targets of Oct-3.

Amino Acid Sequence↗