Biomedical subjects

T Fujiwara

Publications and source records attributed to T Fujiwara.

At least 253 records · Page 14Linked to original sources

PubMed1999

A novel anti-diabetic drug, miglitol, markedly reduces myocardial infarct size in rabbits.

1. We examined whether N-hydroxyethyl-1-deoxynojirimycin (miglitol), a new human anti-diabetic drug with effects to inhibit alpha-1, 6-glucosidase glycogen debranching enzyme and reduce the glycogenolytic rate as well as to inhibit alpha-1,4-glucosidase, could reduce infarct size in the rabbit heart. Rabbits were subjected to 30-min coronary occlusion followed by 48-h reperfusion. 2. The infarct size as a percentage of area at risk was not reduced by pre-ischaemic treatment with 1 mg kg(-1) miglitol (42.7+/-4.0%, n=10) compared with the saline control group (41.7+/-2.3%, n=10). However, it was significantly and dose-dependently reduced by pre-ischaemic treatment with 5 or 10 mg kg(-1) of miglitol (25.7+/-4. 5%, n=10, and 14.6+/-2.4%, n=10, respectively) without altering the blood pressure, heart rate or blood glucose level. However, there was no evidence of an infarct-size reducing effect after pre-reperfusion treatment with 10 mg kg(-1) of miglitol (35.0+/-3.0%, n=10). 3. Another 40 rabbits given 1, 5 and 10 mg kg(-1) of miglitol or saline before ischaemia (n=10 in each) were sacrificed at 30 min of ischaemia for biochemical analysis. Miglitol preserved significantly the glycogen content, and attenuated significantly the lactate accumulation in a dose dependent manner in the ischaemic region at 30 min of ischaemia. 4. Pre-ischaemic treatment, but not pre-reperfusion treatment, with miglitol markedly reduced the myocardial infarct size, independently of blood pressure and heart rate. A dose-dependent effect of miglitol on infarct size, glycogenolysis and lactate formation suggests that the mechanism may be related to the inhibition of glycogenolysis. Thus, miglitol may be beneficial for coronary heart disease as well as diabetes mellitus.

1-Deoxynojirimycin↗

PubMed1999

Overexpression of the p21 sdi1 gene induces senescence-like state in human cancer cells: implication for senescence-directed molecular therapy for cancer.

Normal cells in a culture enter a nondividing state after a finite number of population doubling, which is termed replicative senescence, whereas cancer cells have unlimited proliferative potential and are thought to exhibit an immmortal phenotype by escaping from senescence. The p21 gene (also known as sdi1), which encodes the cyclin-dependent kinase inhibitor, is expressed at high levels in senescent cells and contributes to the growth arrest. To examine if the p21sdi1 gene transfer could induce senescence in human cancer cells, we utilized an adenoviral vector-based expression system and four human cancer cell lines differing in their p53 status. Transient overexpression of p21sdi1 on cancer cells induced quiescence by arresting the cell cycle at the G1 phase and exhibited morphological changes, such as enlarged nuclei as well as a flattened cellular shape, specific to the senescence phenotype. We also showed that p21sdi1-transduced cancer cells expressed beta-galactosidase activity at pH 6.0, which is known to be a marker of senescence. Moreover, the polymerase chain reaction-based assay demonstrated that levels of telomerase activity were significantly lower in p21sdi1-expressing cells compared to parental cancer cells. These observations provide the evidence that p21sdi1 overexpression could induce a senescence-like state and reduce telomerase activity in human cancer cells, suggesting that these novel p21sdi1 functions may have important implications for anticancer therapy.

Adenoviridae↗

PubMed1999

Relationship between shoulder muscle strength and functional independence measure (FIM) score among C6 tetraplegics.

The degree of disability varies widely among C6 tetraplegic patients in comparison with that at other neurological levels. Shoulder muscle strength is thought to be one factor that affects functional outcome. The aim of this study was to examine the relationship between shoulder muscle strength and the Functional Independence Measure (FIM) motor score among 14 complete C6 tetraplegic patients. The FIM motor score and American Spinal Injury Association (ASIA) motor score of these patients were assessed upon discharge. We evaluated muscle strength of bilateral scapular abduction and upward rotation, shoulder vertical adduction and shoulder extension by manual muscle testing (MMT). The total shoulder strength score was calculated from the summation of those six MMT scores. The relationships among ASIA motor score, total shoulder strength score and FIM motor score were analyzed. The total shoulder strength score was significantly correlated with the FIM motor score and the score of the transfer item in the FIM. In the transfer item of the FIM, the total shoulder strength score showed a statistically significant difference between the Independent and Dependent Group. Shoulder muscle strength appears to be an important factor in the functional abilities of those with C6 complete tetraplegia. Functional variation depends on the strength of shoulder muscles, especially among C6 tetraplegics.

Activities of Daily Living↗

PubMed1999

Functional expression of Fas and Fas ligand on human intestinal intraepithelial lymphocytes.

Intestinal intraepithelial lymphocytes (IEL) constitute the first lymphoid compartment to encounter dietary antigens and intestinal pathogens. IEL are proposed to be involved in the defence against bacterial and viral invasion and to play an important role in mucosal immunity. Fas (CD95/APO-1) is a surface receptor that induces apoptotic cell death upon ligation with Fas ligand (FasL). The aim of this study was to examine the expression and function of Fas and FasL on freshly isolated normal human colonic IEL. The expression and function of Fas and FasL on IEL isolated from 40 normal colonic specimens were examined by flow cytometry, reverse transcriptase-polymerase chain reaction, immunohistochemistry, and DNA-release cytotoxicity assay. Virtually all CD3+ IEL (95.2 +/- 4.3%) expressed Fas and were sensitive to agonistic anti-Fas antibody, whereas only 56.6 +/- 8.4% of peripheral T lymphocytes expressed Fas and were resistant to the antibody. We also detected FasL mRNA and protein (40.1 +/- 4.2%) on IEL, and found that IEL exerted FasL-mediated cytotoxicity against Fas-expressing target cells. These findings suggest that human IEL are activated in situ but are tightly regulated by the constitutive expression of functional Fas and FasL to maintain homeostasis of the mucosal immune system.

Adult↗

PubMed1999

1-Methyl-4-phenylpyridinium ion (MPP+) selectively inhibits the replication of mitochondrial DNA.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine is known to cause Parkinsonism in its neurotoxic form, 1-methyl-4-phenylpyridinium ion (MPP+). We have previously reported that MPP+ decreases the content of mitochondrial DNA (mtDNA) independently of the inhibition of complex I in human cells [Miyako, K., Kai, Y., Irie, T., Takeshige, K., and Kang, D. (1997) J. Biol. Chem. 272, 9605-9608]. Here we study the mechanism causing the decrease in mtDNA. MPP+ inhibits the incorporation of 5-bromo-2'-deoxyuridine into mtDNA but not into nuclear DNA, indicating that MPP+ inhibits the replication of mtDNA but not that of the nuclear genome. The replication of mtDNA is initiated by the synthesis of the heavy strand switched from the transcription of the light strand. MPP+ decreases the nascent heavy strands per mtDNA and increases the transcript of the ND6 gene, encoded on light strand, per mtDNA. The amount of mitochondrial transcription factor A is not decreased. These data suggest that the transcription is not inhibited and therefore the transition from transcription to replication of mtDNA is lowered in the MPP+-treated cells. Electron microscopy shows that the number of mitochondria is not decreased in the MPP+-treated cells, suggesting that MPP+ does not affect the overall biogenesis of mitochondria. Thus, MPP+ selectively inhibits the replication of mtDNA.

1-Methyl-4-phenylpyridinium↗

PubMed1999

Molecular cloning, structural characterization and chromosomal localization of human lipoyltransferase gene.

Lipoyltransferase catalyzes the transfer of the lipoyl group from lipoyl-AMP to the lysine residue of the lipoate-dependent enzymes. We isolated human lipoyltransferase cDNA and genomic DNA. The cDNA insert contained a 1119-base pair open reading frame encoding a precursor peptide of 373 amino acids. Predicted amino acid sequence of the protein shares 88 and 31% identity with bovine lipoyltransferase and Escherichia coli lipoate-protein ligase A, respectively. Northern blot analyses of poly(A)+ RNA indicated a major species of about 1.5 kb. mRNA levels of lipoyltransferase were highest in skeletal muscle and heart, showing good correlation with those of dihydrolipoamide acyltransferase subunits of pyruvate, 2-oxoglutarate and branched-chain 2-oxo acid dehydrogenase complexes and H-protein of the glycine cleavage system which accept lipoic acid as a prosthetic group. The human lipoyltransferase gene is a single copy gene composed of four exons and three introns spanning approximately 8 kb of genomic DNA. Some alternatively spliced mRNA species were found by 5'-RACE analysis, and the most abundant species lacks the third exon. The human lipoyltransferase gene was localized to chromosome band 2q11.2 by fluorescence in situ hybridization.

Acyltransferases↗

PubMed1999

Heterogeneity in F-actin polymerization of cord blood polymorphonuclear leukocytes stimulated by N-formyl-methionyl-leucyl-phenylalanine.

BACKGROUND: To elucidate the mechanism responsible for defects of polymorphonuclear leukocyte (PMNL) chemotaxis of neonates, we determined actin polymerization of NBD (7-nitrobenz-2-oxa-diazol)-phallacidin-stained PMNL following stimulation with either N-formyl-methionyl-leucyl-phenylalanine (fMLP) or phorbol myristate acetate (PMA) in cord blood and adult controls. METHODS: We measured F-actin content in PMNL stained with NBD-phallacidin using flow cytometry. RESULTS: Relative F-actin polymerization, that is, a ratio of stimulated F-actin to basal F-actin, was significantly decreased in cord blood PMNL when compared with that of adult PMNL. Distribution of fMLP-stimulated F-actin showed a bimodal pattern, while adult PMNL disclosed a single pattern. Following stimulation with PMA, however, F-actin levels were equal in both cord and adult PMNL. A fluorescein isothiocyanate-conjugated fMLP receptor assay showed no significant difference in binding capacity of fMLP receptors between adult and cord PMNL. CONCLUSION: These results indicate that a deficiency of PMNL chemotaxis in neonates may be due, in part, to decreased relative F-actin polymerization, which may be caused by functional heterogeneity in cord blood PMNL.

Actins↗

PubMed1999

Histologic evaluation of spermatic veins in patients with varicocele.

BACKGROUND: Information concerning varicocele is limited in spite of its clinical importance. This study intends to clarify anatomical features of varicocele. METHODS: Spermatic veins were obtained from varicocele patients at surgery. Areas of two distinct portions (extracellular matrix and smooth muscle) were measured by a micro computer imaging device image analysis system on histologic slides with Masson trichrome stain. In addition, we evaluated the shape and arrangement of the smooth muscle fibers by a scanning electron microscope (SEM). RESULTS: Masson trichrome stain revealed that grade of varicocele partly correlated with thickness of the wall and with amount of the smooth muscle fibers. In the patients with grade 3 varicocele, SEM examination showed marked hypertrophy of longitudinal smooth muscle fibers, which were discriminated clearly from the inner circular fibers. CONCLUSIONS: This study indicated that morphological changes occurred in the muscle layers of varicoceles in the worst grade of varicocele. These structural changes which result from abnormal venous blood circulation may cause development of varicocele, resulting in male infertility.

Adolescent↗

PubMed1999

Evaluation of an implantable motor-driven left ventricular assist device.

A console based implantable motor-driven left ventricular assist device (LVAD) was developed and tested. Ten sheep weighing 42-73 kg (mean, 54.4 kg) were used as the experimental animals. Four animals survived 5-12 h (mean, 9.5 h). The mean pump flow was 1.63 L/min, ranging from 0.8 to 2.5 L/min. The cause of termination was respiratory failure in 3 animals, bleeding in 2, ventricular fibrillation in 2, vent tube obstruction in 1, thrombus formation in 1, and mechanical failure of the driving console in 1. Following the in vivo studies, the computer regulated controller was tested in a mock circulatory system. The LVAD provided 5.34 L/min of maximum output against a mean afterload of 80 mm Hg with a filling pressure of 15 mm Hg when the pump rate was 80 bpm in the fixed rate mode. With an increase in the pump afterload from 80 to 140 mm Hg, the total system efficiency varied from 7.81 to 8.34% when the pump preload was 15 mm Hg. An ultracompact, completely implantable electromechanical VAD has been under development. This device should fit in a 60 kg adult. As the next step, we are preparing to implant this ultracompact implantable VAD with an electronic controller in an animal model with better results being expected.

Animals↗

PubMed1999

The influence of non-paretic leg movement on muscle action in the paretic leg of hemiplegic patients.

The aim of this investigation was to study the effect of non-involved-side exercise on the involved (paretic) leg-muscle of patients with stroke. Each of the ten adults studied attempted to perform, while seated, a predetermined sequence of the following actions : (1) a voluntary knee extension on the involved side; (2) a maximal, isometric knee-flexion on the non-involved side; (3) a maximal, isometric knee-flexion on the non-involved side with counter-resistance (in front of the ankle joint) on the involved side. The root-mean-square voltage was measured across the rectus femoris, the medial hamstring, the tibialis anterior, and the medial gastrocnemius muscles (on the involved side) with surface electrodes. The root-mean-square voltages of the involved-side rectus femoris and the tibialis anterior muscles were found to increase substantially during non-involved-side knee flexion relative to that detected for voluntary knee extension on the involved side. The voltage of the rectus femoris muscle increased substantially also when counter-resistance was present. There was no similar substantial increase of muscular activity, in the medial hamstring and medial gastrocnemius, induced by contralateral isometric knee-flexion. This study suggests that, among patients with severe hemiplegia, isometric knee flexion in the non-involved side may be useful for facilitating the paretic rectus femoris and tibialis anterior muscular activities.

Aged↗

PubMed1999

Internal absorbed dose estimation by a TLD method for 18F-FDG and comparison with the dose estimates from whole body PET.

The thermoluminescent dosimeter (TLD) method has been proposed as a useful tool for estimating internal radiation absorbed dose in nuclear medicine. An efficient approach to verify the accuracy of the TLD method has been performed in this study. Under the standard protocol for 2-[F-18]fluoro-2-deoxy-D-glucose (18F-FDG), whole body PET experiments and simultaneous body surface dose measurements by TLDs were performed on six normal volunteers. By using the body surface dose measured with TLDs, the cumulated activities of nine source organs were estimated with a mathematical unfolding technique for three different initial guesses. The accuracy of the results obtained by the TLD method was investigated by comparison with the actual cumulated activity of the same source organs measured by whole body PET. The cumulated activities of the source organs obtained by the TLD method and whole body PET show a significant correlation (correlation coefficient, r > 0.98, level of confidence, p < 0.001) with each other. The mean effective doses in this study are 3.2 x 10(-2) mSv MBq(-1) obtained from the TLD method and 2.9 x 10(-2) mSv MBq(-1) obtained from the whole body PET. Good agreement between the results of the TLD method and whole body PET was observed.

Adult↗

PubMed1999

Expression and differential intracellular localization of two major forms of human 8-oxoguanine DNA glycosylase encoded by alternatively spliced OGG1 mRNAs.

We identified seven alternatively spliced forms of human 8-oxoguanine DNA glycosylase (OGG1) mRNAs, classified into two types based on their last exons (type 1 with exon 7: 1a and 1b; type 2 with exon 8: 2a to 2e). Types 1a and 2a mRNAs are major in human tissues. Seven mRNAs are expected to encode different polypeptides (OGG1-1a to 2e) that share their N terminus with the common mitochondrial targeting signal, and each possesses a unique C terminus. A 36-kDa polypeptide, corresponding to OGG1-1a recognized only by antibodies against the region containing helix-hairpin-helix-PVD motif, was copurified from the nuclear extract with an activity introducing a nick into DNA containing 8-oxoguanine. A 40-kDa polypeptide corresponding to a processed form of OGG1-2a was detected in their mitochondria using antibodies against its C terminus. Electron microscopic immunocytochemistry and subfractionation of the mitochondria revealed that OGG1-2a locates on the inner membrane of mitochondria. Deletion mutant analyses revealed that the unique C terminus of OGG1-2a and its mitochondrial targeting signal are essential for mitochondrial localization and that nuclear localization of OGG1-1a depends on the NLS at its C terminus.

Alternative Splicing↗

PubMed1999

Synthesis of pyrrole-imidazole-duocarmycin polyamide and its sequence selective DNA alkylation.

The new solid phase synthesis of sequence-specific DNA alkylating polyamides containing segment A of Du86 (Duo), N-methylimidazole (Im) and N-methylpyrrole (Py) amino acids is described. New monomer building block N-carboxylmethyl Py (Pyc) was synthesized from 2-methylpyrrolecarboxylate by eight steps. After normal coupling of FMOC-protected-Im and -Py monomer, the deprotection of silyl group generates free carboxylic acid. Introduction of various types of functional groups on solid support will be presented.

Alkylation↗

PubMed1999

HPC-1/syntaxin 1A suppresses exocytosis of PC12 cells.

The membrane protein syntaxin (originally named HPC-1) is involved in vesicle trafficking and required for neurotransmitter release at nerve terminals. The presence of syntaxin on target membranes is hypothesized to confer specificity to targeting and fusion via interactions with complementary vesicle-associated proteins. To elucidate the function of syntaxin 1A in exocytosis, HPC-1/syntaxin 1A-reduced PC12h cells (PC12h/Deltasyx) that were stably transfected with a plasmid for antisense syntaxin 1A expression were constructed. Depolarizing stimulation of PC12h/Deltasyx enhanced dopamine release, compared with PC12h. There was a strong inverse correlation between syntaxin 1A protein expression and enhancement of dopamine release. Reduction of syntaxin 1A had no effect on increase of the cytoplasmic free Ca2+ concentration by depolarized stimulation. Moreover, PC12h/Deltasyx clones similarly enhanced of exocytosis by native secretagogues. These results indicate that syntaxin 1A has more than one function in exocytosis.

Animals↗

PubMed1999

Induction of apoptosis by gallic acid in lung cancer cells.

The apoptosis-inducing effect of gallic acid (3,4,5-trihydroxybenzoic acid) was investigated in four human lung cancer cell lines, SBC-3 (small cell carcinoma), EBC-1 (squamous cell carcinoma), A549 (adenocarcinoma) and SBC-3/CDDP (cisplatin-resistant subclone of SBC-3). Gallic acid induced apoptosis in a dose-dependent manner as evidenced by analyses of DNA fragmentation, changes in cell morphology and loss of viability. Fifty percent inhibitory concentration (IC50) values of gallic acid on the cell viability of SBC-3, EBC-1 and A549 were around 10, 20 and 60 microg/ml, respectively. The IC50 value for SBC-3/CDDP cells was almost the same as that of SBC-3, suggesting that susceptibility of cells to gallic acid-induced apoptosis is not altered by the acquisition of cisplatin resistance. The apoptotic process was effectively triggered by 30 min exposure to gallic acid. A caspase inhibitor and alpha-tocopherol effectively prevented the gallic acid-induced apoptosis, indicating the involvememt of caspase activation and oxidative processes during the course of apoptosis in gallic acid-treated cancer cells. These findings suggest the possible applicability of gallic acid in lung cancer therapy, especially to circumvent resistance to anti-cancer drugs.

Adenocarcinoma↗

PubMed1999

FDG PET evaluation of residual masses and regrowth of abdominal lymph node metastases from colon cancer compared with CT during chemotherapy.

Fluorine-18-2-deoxy-2-fluoro-D-glucose (F-18 FDG) PET may be more suitable for follow-up after cancer treatment than other morphologic approaches, because it reflects tumor viability. A patient with abdominal lymph node metastases from colon cancer was followed by CT and F-18 FDG PET during chemotherapy. F-18 FDG PET tumor images changed in accordance with the clinical progress, whereas CT findings were relatively unchanged. This case clearly shows the utility of F-18 FDG PET for follow-up during cancer chemotherapy.

Abdominal Neoplasms↗

PubMed1999

Sclerosing mediastinitis: findings on fluorine-18 fluorodeoxyglucose positron emission tomography.

Whole-body serial positron emission tomography scanning was done using fluorine-18 fluorodeoxyglucose (F-18 FDG) in a patient with a mediastinal mass. Uptake correlated well with the clinical symptoms and aggressiveness of the disease. Based on the F-18 FDG findings, a biopsy specimen was taken from the active region of the mass, which confirmed the diagnosis of sclerosing mediastinitis.

Biopsy↗

PubMed1999

Wavelength dependence of photoparoxysmal responses in photosensitive patients with epilepsy.

PURPOSE: We tried to specify the relation between the photoparoxysmal response (PPR) and the wavelength spectra of flashing light in various photosensitive epileptic syndromes in the physiologic state. METHODS: Intermittent photic stimulation (IPS) by a Grass PS22 photic stimulator was performed with wavelength-specific optical filters in photosensitive patients with epilepsy (idiopathic generalized epilepsy, IGE; hereditary dentatorubral-pallidoluysian atrophy, DRPLA) and photosensitive subjects without epilepsy. RESULTS: Five of 19 normal trichromat patients with IGE and an IGE patient with deuteranomaly showed wavelength-dependent PPRs. The wavelength-dependent PPRs were elicited only by IPS containing wavelength spectra approximately 700 nm in the normal trichromat patients. Two of four patients with DRPLA showed wavelength-dependent PPRs, and two other DRPLA patients showed quantity-of-light-dependent PPRs. Quantity-of-light-dependent PPRs are elicited by IPS containing more than a certain quantity of light, independent of the wavelength composition of the flashing light. Two of five subjects without epilepsy showed wavelength-dependent PPRs. CONCLUSIONS: There are wavelength-dependent and quantity-of-light-dependent pathophysiologic mechanisms for eliciting PPRs by low-luminance IPS. Consideration of the quantity and wavelength composition of light from electronic screens will lead to the prevention of photosensitive seizures induced by electronic screen games.

Cerebral Cortex↗