Search PubMed⌕ Search

Biomedical subjects

I Saito

Publications and source records attributed to I Saito.

At least 145 records · Page 8Linked to original sources
PubMed1999

Fas ligand-mediated exocrinopathy resembling Sjögren's syndrome in mice transgenic for IL-10.

Although IL-10 has been implicated in the pathogenesis of several autoimmune diseases, the mechanisms by which this cytokine mediates inflammatory lesions remain to be elucidated. Exocrine gland destruction is an important early step in the development of Sjögren's syndrome. To better understand the role of IL-10 in Sjögren's syndrome, we made transgenic mice in which the mouse IL-10 gene was regulated by the human salivary amylase promoter. Transgenic expression of IL-10 induced apoptosis of glandular tissue destruction and lymphocyte infiltration consisting primarily of Fas-ligand (FasL)+ CD4+ T cells, as well as in vitro up-regulation of FasL expression on T cells. These data suggest that overexpression of IL-10 in the glands and their subsequent Fas/FasL-mediated bystander tissue destruction is a causal factor in the development of this disease.

Animals↗
PubMed1999

Prevalence of Epstein-Barr virus in oral squamous cell carcinoma.

Forty-six samples of oral squamous cell carcinoma (OSCC) were evaluated for the prevalence of Epstein-Barr virus (EBV) infection by the polymerase chain reaction (PCR), Southern blot hybridization, and in situ hybridization (ISH). EBV DNA was detected in 7 (15.2 per cent) out of 46 samples by a combination of PCR and Southern blot hybridization methods. All seven positive samples showed well-differentiated carcinoma, thus suggesting a possible relationship between EBV infection and the degree of differentiation of carcinoma tissue. Latent infection membrane protein 1 (LMP1) was detected immunohistochemically in six of the EBV-positive OSCCs. However, no signal of the EBV-encoded small RNA (EBER)-1 was demonstrated by the ISH method. No significant relationship was observed between EBV infection and lymph node metastasis. A follow-up study (range from 4.4 to 79 months; mean 34.9 months) showed no recurrence or death to occur in the EBV-positive patients, which thus suggested a good prognosis for EBV-positive OSCC patients.

Adult↗
PubMed1999

Effective adenovirus-mediated gene expression in adult murine skeletal muscle.

We established an efficient method for obtaining expression of a foreign marker gene transferred in vitro into myoblasts and in vivo into adult mouse skeletal muscles using adenovirus vector. After infection of the C2 myoblasts with the adenovirus vector containing the beta-actin promoter with cytomegalovirus (CMV) enhancer (CAG promoter) AxCALacZ, significantly greater number of cells express beta-galactosidase when compared with the adenovirus vector expressing the lacZ gene under the control of the SR alpha viral terminal repeat promoter (AxSRLacZL) or the myosin heavy chain (MHC) IIB promoter (AxMHCLacZ). We also injected AxCALacZ into the skeletal muscles of 5- to 6-week-old C57BL/10 mice and determined that more than 60% of their muscle fibers expressed the lacZ gene 7 days after injection. The CAG promoter may have application in the development of gene therapy for Duchenne muscular dystrophy (DMD) using adenovirus vector.

Adenoviridae↗
PubMed1999

Potential errors resulting from sex and age difference in assessing family history of diabetes.

BACKGROUND: Diabetes mellitus occurs nearly exponentially with aging and its occurrence differs between men and women in adulthood. Therefore, the sex and age of family members should be considered in assessing the family history. In this report the effects of sex and age on the positivity of family history were estimated numerically. METHODS: Sex- and age-specific proportion of a positive history of diabetes mellitus among 24,273 family members was obtained from a questionnaire survey of 2,316 high school students in Japan. By analyzing the sex- and age-specific proportion with the logistic regression model, odds ratios were estimated which indicated potential bias or misclassification resulting from sex and age differences. RESULTS: The odds ratios were 1.97 (95% confidence interval, 1.74-2.23) for the sex difference and 1.05 (95% confidence interval, 1.04-1.05) for an age difference of 1 year. This indicated that a male family member had a 1.97 times higher chance of having a positive history than a female member and that a positive history increased by (1.05)y, where y was age difference in years. CONCLUSION: A control for sex and age of family members will be required in assessing the family history of diabetes mellitus as a risk factor.

Adolescent↗
PubMed1999

Continuous monitoring of cerebrospinal fluid acid-base balance and oxygen metabolism in patients with severe head injury: pathophysiology and treatments for cerebral acidosis and ischemia.

INTRODUCTION: Continuous monitoring of cerebral acid-base balance and oxygen metabolism has been introduced in neurointensive care settings. The hypothesis of this study utilizing multimodal neuromonitoring modalities is that hyperventilation and hypothermia improve cerebral acidosis through prevention of cerebral ischemia aggravation in patients with severe head injury. PATIENTS AND METHODS: Continuous monitoring of cerebrospinal fluid (CSF) pH, PCO2, HCO3-, base excess (BE), PO2, SO2, temperature, lactate and pyruvate (La and Py) measurements were conducted in 8 patients with severe head injury. Temperature-corrected CSF parameters were correlated with those in the jugular blood including oxygen saturation (SjO2), regional oxygen saturation (rSO2), intracranial pressure (ICP) and cerebral perfusion pressure (CPP), jugular blood temperature (Tjb), and endtidal PCO2 (PetCO2). Therapeutic significance of hyperventilation and hypothermia was evaluated. RESULTS: 1) CSF acidosis was observed in all cases (minimum pH 6.59-7.17) due to increased CSF PCO2 and/or decreased CSF HCO3- and tended to associate with abnormal ICP and/or CPP or ischemic episodes indicated by CSF PO2 and SO2, rSO2, and/or SjO2 during monitoring. 2) It was more obvious in CSF than in jugular blood that increased PCO2, La and Py, and/or decreased HCO3- resulted in decreased BE and pH. 3) Decreased CSF PO2 and SO2 only correlated with severe CSF acidosis. 4) Hyperventilation: Decreased PetCO2 did not always closely correlate with CSF PCO2 decrease and CSFpH increase. 5) Hypothermia: There were negative correlations of Tjb with CSF pH and SO2 in all cases, though correlation coefficients were not always high. CONCLUSIONS: CSF acidosis caused by increased CSF PCO2, La and Py, and/or decreased HCO3- tended to associate with abnormal ICP and CPP, and desaturation indicated by CSF SO2, rSO2, and/or SjO2. Hypothermia rather than hyperventilation tends to improve cerebral acidosis and ischemia.

Acidosis↗
PubMed1999

Estrogen deficiency accelerates autoimmune exocrinopathy in murine Sjögren's syndrome through fas-mediated apoptosis.

Estrogenic action has been suggested to be responsible for the strong female preponderance of autoimmune diseases, but the role of estrogens in the female has not been well characterized. We evaluated the effects of estrogen deficiency in a murine model for autoimmune exocrinopathy of Sjögren's syndrome (SS). Severe destructive autoimmune lesions developed in the salivary and lacrimal glands in estrogen-deficient mice, and these lesions were recovered by estrogen administration. We detected an intense estrogen receptor in splenic CD8(+) T cells compared with that in CD4(+) T cells, and concanavalin-A-stimulated blastogenesis of splenic CD8(+) T cells with estrogens was much higher than that of CD4(+) T cells. We found a significant increase in serum autoantibody production against the organ-specific autoantigen alpha-fodrin. Moreover, an increased proportion of TUNEL+ apoptotic epithelial duct cells was observed in estrogen-deficient mice. It was demonstrated that Fas-mediated apoptosis in cultured salivary gland cells was clearly inhibited by estrogens in vitro. These results indicate that dysfunction of regulatory T cells by estrogen deficiency may play a crucial role on acceleration of organ-specific autoimmune lesions, and estrogenic action further influences target epithelial cells through Fas-mediated apoptosis in a murine model for SS.

Animals↗
PubMed1999

Mouse senile amyloid deposition is suppressed by adenovirus-mediated overexpression of amyloid-resistant apolipoprotein A-II.

Apolipoprotein A-II (apoA-II), the second most abundant apolipoprotein of serum high density lipoprotein, deposits as an amyloid fibril (AApoAII) in old mice. Mouse strains with a high incidence of senile amyloidosis have the type C apoA-II gene (Apoa2(c)), whereas the strains with a low incidence of amyloidosis have the type B apoA-II gene (Apoa2(b)). In this study, to investigate whether the type B apoA-II protein inhibits the extension of amyloid fibrils, we constructed an adenovirus vector bearing the Apoa2(b) cDNA (Adex1CATApoa2(b)), which is expressed under the control of a hepatocyte-specific promoter. The mice were infected with Adex1CATApoa2(b) before induction of amyloidosis by the injection of AApoAII amyloid fibril seeds. Compared with the mice infected with the control virus, amyloid deposition was suppressed significantly in the mice infected with Adex1CATApoa2(b). Fluorometry using thioflavine T also revealed that AApoAII fibril extension was inhibited by the addition of type B apoA-II in vitro. Thus, we propose that Apoa2(b) contributes as an active inhibitor of amyloid fibril extension and overexpression of amyloid-resistant gene variant may be an attractive therapeutic target in amyloidosis.

Adenoviridae↗
PubMed1999

Adenovirus-mediated gene expression in the septal cells of cirrhotic rat livers.

BACKGROUND/AIMS: Liver cirrhosis is characterized by the formation of fibrous septa following hepatic necrosis and fibrosis, and finally progression to severe hepatic failure and/or hepatocellular carcinoma. To establish effective therapy for cirrhosis using a designed gene, we examined whether recombinant adenovirus vectors could transfer foreign genes into the septal cells of cirrhotic livers. METHODS: Rats with cirrhosis induced by 4-8 weeks treatment with carbon tetrachloride were intravenously infected with a recombinant adenovirus Adex1CALacZ bearing a bacterial lacZ gene. Expression of the transferred gene was determined by X-gal staining. The infectivity of the vectors in vitro was examined using slice cultures from the cirrhotic rat livers. RESULTS: In normal rat livers, almost all hepatocytes expressed beta-galactosidase from the recombinant adenovirus vectors. In rat liver fibrosis, the adenovirus-mediated gene transfer to hepatocytes is markedly reduced compared with normal rat liver. In cirrhosis, there is an even stronger reduction in the number of transduced hepatocytes. On the other hand, in vitro infection to the slice culture demonstrated that the cirrhotic hepatocytes still maintained adenovirus infectivity. Moreover, in the kidney, which is the second target organ of adenovirus, there was no difference in infectivity between normal and cirrhotic rats. CONCLUSION: The recombinant adenovirus intravenously transmitted the foreign gene to septal cells in extranodular fibrous septa, rather than to hepatocytes within small nodules. Therefore, septal cells in the cirrhotic liver should be targeted with the adenovirus vector for a successful in vivo therapeutic strategy.

Adenoviridae↗
PubMed1999

Exogenous expression of p16INK4a is associated with decrease in telomerase activity.

In this study, gene transfection was used to determine whether the exogenous expression of p16INK4a modulated the biological characteristics of glioblastoma cells. The human glioblastoma cell line U87MG was doubly transfected with the plasmids pVgRXR and pIND harboring the wild-type p16 gene. The expression of p16INK4a in the resulting transfectants was regulated by the addition of the ecdysone homologue, muristerone A. When the cells expressed p16INK4a, their growth capacity was reduced and morphological changes such as an increase in cell size and cellular flattening were observed. The analysis of cell cycle regulation provided evidence that cells expressing p16INK4a were inhibited from entry into the cell cycle, as assessed by Ki-67 antigen expression. In addition, it was observed that the exogenous expression of p16INK4a was associated with decrease in telomerase activity.

Brain Neoplasms↗
PubMed1999

Cancer gene therapy using a pro-apoptotic gene, caspase-3.

Caspase-3 is a member of the cysteine protease family, which plays a crucial role in apoptosis. We applied the human caspase-3 gene as a novel form of anticancer gene therapy. Overexpression of human caspase-3 alone could not induce apoptosis of tumor cell lines, but apoptosis was markedly enhanced by the addition of etoposide. In an AH130 liver tumor model, transduction of human caspase- 3, but not the empty vector, induced extensive apoptosis and reduced tumor volume when combined with etoposide administration. However, this effect was not observed with a Bcl-2 overexpressing tumor. In conclusion, caspase-3 gene transduction accompanied by an additional death stimulus may be a useful method of anticancer gene therapy, except for Bcl-2 overexpressing tumors.

Adenoviridae↗
PubMed1999

Flowcytometric analysis of bronchoalveolar lavage fluid cells in polymyositis/dermatomyositis with interstitial pneumonia.

OBJECTIVE: Interstitial lung disease (ILD) is a complication occurring in 10-30% of patients with polymyositis/dermatomyositis (PM/DM) as well as in those with progressive systemic sclerosis (PSS). Clinical features are different between these two disease states, notably with respect to the duration of manifestations, pathological findings, response to steroid therapy etc. However, dissimilarities in pulmonary inflammatory cell characteristics, which, if present at all, would be of critical importance, remain as yet to be clarified. METHODOLOGY: The phenotypes of lymphocytes and alveolar macrophages in bronchoalveolar lavage fluid (BALF) were analysed to elucidate phenotypic peculiarity of pulmonary inflammatory cells of ILD in PM/DM. Eight PM/DM patients with ILD (mean age 47.9 years) were examined by bronchofibrescopy under local anaesthesia. Bronchoalveolar lavage was performed from the right middle lobe using four 50 mL aliquots of normal saline and the recovered fluid was compared with BALF of ILD in PSS. RESULTS: Bronchoalveolar lavage fluid cells of PM/DM patients with ILD showed an increased percentage of CD8+ lymphocytes, in particular CD8+ histocompatibility leucocyte antigen-DR positive lymphocytes and CD8+ CD11b-lymphocytes, both of which represent cytotoxic T cells. However, phenotypic differences in these lymphocytes were not found between PM and DM. The percentage of alveolar macrophages with expression of histocompatibility leucocyte antigen-DQ was significantly different among the three groups (PM/DM, PSS, healthy volunteers). CONCLUSIONS: Cytotoxic T cells may be major pulmonary inflammatory cells of ILD in PM/DM with no apparent difference between PM and DM. In contrast, ILD in PSS was suggested as being likely to be characterized by activated macrophage.

Adult↗
PubMed1999

Implantation of the undulation pump total artificial heart in the goat.

The undulation pump total artificial heart (UPTAH) was developed by using small-size continuous-flow displacement-type blood pumps (undulation pump). To clarify and improve the problems accompanied by the implantation in the chest, 14 animal experiments were performed on goats weighing 41.3-79.2 kg. The UPTAH could be implanted in the chest of all goats and was driven with a modulation pulsatile mode. The first problem was the atrial suction effect. This problem could be prevented to some extent by developing the soft disk and by improving atrial cuffs. An automatic detection and releasing of the atrial suction effect was also tried. The next problem was acute lung edema accompanied by the postural change of the animal. Development of the automatic control of left atrial pressure could prevent this problem. Small blood leakage from a pinpoint hole in the seal membrane was the next problem. Improvement of the manufacturing procedure of the membrane prevented this. With these improvements, a 10 day survival could be obtained with this unique implantable total artificial heart.

Acute Disease↗
PubMed1999

Present status of the total artificial heart at the University of Tokyo.

At the University of Tokyo, various types of total artificial heart (TAH) systems have been studied since 1959. At the present time, 2 types of implantable TAH have been developed. One is an undulation pump TAH (UPTAH) and the other is a flow transformed pulsatile TAH (FTPTAH). Using the UPTAH, 14 cases of implantation were performed in goats and 10 days' survival obtained. The new type of FTPTAH is under a prototype study. To prevent ring thrombus, a polyurethane membrane valve, a jellyfish valve, has been developed. The longest in vivo experiences with this valve in the TAH blood pump have been 312 days in the left side blood pump and 414 days in the right side blood pump. Conductance and arterial pressure based control (1/R control) can realize the physiological control of the TAH. Using 1/R control, 532 days of survival could be obtained in a goat with a paracorporeal TAH. The technique required to apply this control method to a implantable TAH is under development. We have proposed a new 5 year research project of the implantable TAH entitled "Comprehensive Basic Research on the Development of a Japanese Original Implantable Total Artificial Heart" to The Ministry of Welfare.

Animals↗
PubMed1999

Replication in vitro and cleavage by restriction endonuclease of 5-formyluracil- and 5-hydroxymethyluracil-containing oligonucleotides.

PURPOSE: To investigate the biological consequences of 5-formyluracil (5-foU) and 5-hydroxymethyluracil (5-hmU). MATERIALS AND METHOD: The authors constructed 22-mer oligonucleotides containing a 5-foU or 5-hmU residue at the same sites. The effects of such modifications on the ability to serve as a template for DNA polymerase and on the cleavage by sequence-specific restriction endonuclease were examined. RESULTS: The Klenow fragment of DNA polymerase I and Thermus thermophilus DNA polymerase read through the sites of 5-foU and 5-hmU in the templates. 5-FoU directed the incorporation of dCMP in addition to dAMP opposite the lesion during DNA synthesis. The DNA polymerases incorporated only dAMP opposite the 5-hmU. The substitution of thymine by 5-foU within the recognition site of the restriction endonucleases HincII and SalI inhibited or prevented the cleavage by the enzymes, whereas the enzymes cleaved the 5-hmU-containing oligonucleotides at the same rate as the T-containing oligonucleotides. CONCLUSIONS: These results indicated that the 5-foU-A base pair is less stable than the T-A base pair and that 5-foU can form a base pair with C in addition to A. It was also demonstrated that the oxidation of thymine to 5-hmU does not result in substantial deterioration.

Animals↗
PubMed1999

DNA HOMO as a new landmark for nucleic acid properties. ab initio calculations and experimental mapping.

Of the non-covalent binding forces in DNA-drug or DNA-protein interaction, electrostatic interaction, stacking interaction, hydrogen bonds and hydrophobic effect have been well established. However, only a few HOMO-LUMO interaction in DNA have been reported. We examined the ab initio calculations of B-DNA duplex 5-mers. Based on the calculated results, we investigated the mapping of HOMO experimentally and found that DNA cleavage patterns with Co(II) and BPO (Benzoyl peroxide) were in good agreement with the ab initio calculation results.

Base Sequence↗
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

Amplification of bleomycin-induced DNA cleavage by pyrrole triamide.

We investigated the amplification of bleomycin-induced DNA cleavage by synthetic pyrrole triamide (PyPyPy) using 32P-labeled DNA fragments obtained from human genes. Peplomycin, a kind of bleomycins, plus Fe(II) caused DNA cleavage at the 5'-GC-3' and 5'-GT-3' sequences (damaged bases are underlined). The addition of PyPyPy enhanced the cleavage at cytosine and thymine residues 3' to consecutive guanines, particularly at the 5'-GGGGC-3' and 5'-GGGGT-3' sequences. These results suggest that PyPyPy binds to DNA to induce its conformational change, resulting in alteration of the site specificity and amplification of DNA cleavage. The present study on amplifiers of antitumor drugs would show a novel approach to the establishment of more effective chemotherapy.

Bleomycin↗