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Biomedical subjects

I Saito

Publications and source records attributed to I Saito.

At least 163 records · Page 9Linked to original sources
PubMed1999

Reversible photoligation of DNA via 5-vinyldeoxyuridine.

We report a novel non-enzymatic template-directed reversible photoligation of oligodeoxyribonucleotides (ODNs). In this photoligation system, a modified ODN containing 5-vinyldeoxyuridine at 5'-end reacts by photoirradiation at 366 nm with cytosine and thymine at the 3'-end of another ODN in the presence of a complementary template to yield a ligated ODN quantitatively. The ligated ODN can be split site-selectively to regenerate the parent ODN by photoirradiation at 302 nm.

Base Sequence↗
PubMed1999

Cleavage of parallel-stranded DNA duplex by peplomycin metal complexes.

Peplomycin-mediated degradation of parallel-stranded (ps) duplex was investigated. It was found that Co- and Fe-peplomycins degraded ps DNA duplex by 4'-hydrogen abstraction at 5'-GPy (pyrimidine) site in a similar manner to that of antiparallel B-DNA. While the orientation of two strands of ps and B-form DNA duplexes are reversed, peplomycin metal complex can bind to ps DNA duplex to cause oxidative DNA damage. These results indicate that peplomycin metal complex mainly interacts with one strand which is damaged.

Base Sequence↗
PubMed1999

New aneurysm clip and applier for narrow spaces: technical note.

OBJECTIVE: Aneurysm surgery carries considerable risk to the patient, in part because the surgical field can be so constricted that accurate placement of the aneurysm clip is impeded. In fact, most aneurysm clip appliers are so bulky that they can impair the surgeon's view, if the field is tight. We describe a system of aneurysm clips and appliers that have a very low profile and consequently allow better visualization of the operative field at critical moments during surgery. INSTRUMENTATION: A new system of clips for aneurysm surgery was developed to overcome some of the deficiencies of conventional sets. The new clip blades are opened from inside the spring, so the clip blades are clearly seen as they are applied across the base of the aneurysm. In addition, these clips can be angled in any desired direction in the applier, which makes their application easier. A third advantage is that the clip applier is used as a clip remover should adjustment or reapplication of the clip be necessary. RESULTS: Thirty aneurysms were obliterated with the new clips without any complications attributable to the clips. The new instruments allowed the safe application of clips to aneurysms in deep, confined, and anatomically complex spaces, such as aneurysms of the basilar tip and anterior communicating artery. CONCLUSION: The newly described system of aneurysm clips and appliers appears to have significant advantages over other currently available systems.

Animals↗
PubMed1999

Treatment of dry eye by autologous serum application in Sjögren's syndrome.

AIM: To evaluate the efficacy of autologous serum application for the treatment of dry eye in Sjögren's syndrome. METHODS: The stability of essential components (EGF, vitamin A, and TGF-beta) in preserved serum were examined following preservation at 4 degrees C and -20 degrees C. In a primary clinical trial, 12 patients with Sjögren's syndrome were treated with autologous serum (diluted to 20% with sterile saline) for 4 weeks, and vital staining of the ocular surface was compared before and after treatment. The effects of serum on mucin (MUC-1) expression were observed in cultured conjunctival epithelial cells in vitro. RESULTS: EGF, vitamin A, and TGF-beta were well preserved for up to 1 month in the refrigerator at 4 degrees C and up to 3 months in the freezer at -20 degrees C. Rose bengal and fluorescein scores improved significantly from the initial scores of 5.3 and 5.6 to 1.7 and 2.5 after 4 weeks, respectively. The additive effect of human serum for cultured conjunctival epithelial cells showed significant MUC-1 upregulation on the cell surface. CONCLUSION: Autologous serum application is a safe and efficient way to provide essential components to the ocular surface in the treatment of dry eye associated with Sjögren's syndrome.

Blood↗
PubMed1999

Possible involvement of IL-12 expression by Epstein-Barr virus in Sjögren syndrome.

AIM: To determine the correlation between interleukin 12 (IL-12) expression and Epstein-Barr virus (EBV) in Sjögren syndrome. METHODS: Indirect immunohistochemical technique, enzyme linked immunosorbent assay (ELISA), and immunoblot analysis were used to investigate IL-12 expression by EBV activation, using 13 surgical specimens and four B cell lines. RESULTS: Marked expression of IL-12 was found in the epithelial cells and the infiltrating B cells of salivary gland tissues from patients with Sjögren syndrome (six of 10 cases), but not in those from normal individuals (none of three cases). A striking topographic correlation between IL-12 and EBV was found. In addition, levels of IL-12 production by B cell lines were clearly enhanced by EBV activation in vitro. CONCLUSIONS: IL-12 expression closely reflects the intracellular event of EBV activation in Sjögren syndrome, and may contribute to the T helper cell type 1 (Th1) cytokine overexpression seen in this disease.

Adult↗
PubMed1999

Reversal of hypopigmentation in phenylketonuria mice by adenovirus-mediated gene transfer.

Phenylketonuria (PKU) is caused by deficiency of phenylalanine hydroxylase (PAH) in the liver. Patients with PKU show increased L-phenylalanine in blood, which leads to mental retardation and hypopigmentation of skin and hair. As a step toward gene therapy for PKU, we constructed a replication-defective, E1/E3-deleted recombinant adenovirus harboring human PAH cDNA under the control of a potent CAG promoter. When a solution containing 1.2 x 10(9) plaque-forming units of the recombinant adenovirus was infused into tail veins of PKU model mice (Pah(enu2)), predominant expression of PAH activity was observed in the liver. The gene transfer normalized the serum phenylalanine level within 24 h. However, it also provoked a profound host immune response against the recombinant virus; as a consequence, the biochemical changes lasted for only 10 d and rechallenge with the virus failed to reduce the serum phenylalanine concentration. Administration of an immunosuppressant, FK506, to mice successfully blocked the host immune response, prolonged the duration of gene expression to more than 35 d, and allowed repeated gene delivery. We noted a change in coat pigmentation from grayish to black after gene delivery. The current study is the first to demonstrate the reversal of hypopigmentation, one of the major clinical phenotypes of PKU in mice as well as in humans, by adenovirus-mediated gene transfer, suggesting the feasibility of gene therapy for PKU.

Adenoviridae↗
PubMed1999

Sexual differences in relationships between birth weight or current body weight and blood pressure or cholesterol in young Japanese students.

This study was designed to examine the relationships between birth weight or current body weight and blood pressure (BP) or cholesterol in 178 Japanese high school students (98 male, 80 female, age 15-16 yr). All subjects were born after a full-term pregnancy (gestational age > or = 38 wk) with a birth weight > or = 2,500 g; these data were obtained from routine obstetrical records. At a health check-up, nurses used an automatic device to perform two consecutive BP measurements with each subject in a sitting position after resting for at least 5 min. Serum total and high-density lipoprotein (HDL) cholesterol levels were measured. Birth weight was not related to BP, but was inversely related to serum total cholesterol in both males (r= -0.241, p < 0.05) and females (r= -0.351, p < 0.01). Current body weight was significantly related to systolic BP (r=0.369, p<0.01), diastolic BP (r=0.216, p<0.05), and HDL cholesterol level (r= -0.224, p < 0.05) in males, but not in females. Although no relationship was demonstrated between birth weight and BP level in young Japanese students without intrauterine growth retardation, an inverse relationship between birth weight and serum total cholesterol level was found. There was a gender difference in the relationship between current body weight and either BP or HDL cholesterol in these subjects.

Adolescent↗
PubMed1999

[Angiotensin II receptor antagonists: a review of the development and future perspective].

Pharmacological blockade of the renin-angiotensin system has been found to be a safe and efficacious way to treat hypertension and congestive heart failure. The success of the angiotensin converting enzyme inhibitors has led to interest in alternative ways to block the renin-angiotensin system. Angiotensin II receptor antagonists are a new class of anti-hypertensive drugs that provide a specific blockade of the effects of angiotensin II. Losartan potassium, the first compound of this class, has recently been approved in Japan. It seems likely that the angiotensin receptor antagonists will be suitable to first-line therapy and use of this class for treatment of hypertension will dramatically increase in Japan because of the excellent clinical and laboratory safety profiles.

Angiotensin Receptor Antagonists↗
PubMed1999

Traumatic Horner syndrome without anhidrosis.

In a patient with a traumatic avulsion of the arm, magnetic resonance imaging showed the exact site of the lesion that produced Horner syndrome with preservation of sweating on the face.

Adult↗
PubMed1999

Regulation of human leukocyte antigen expression in human conjunctival epithelium.

PURPOSE: To demonstrate that interferon-gamma (IFN-gamma) is the key cytokine responsible for the upregulation of HLA-DR antigen in conjunctival epithelial cells of Sjogren syndrome (SS) patients. METHODS: Flow cytometry of conjunctival epithelial cells from SS and non-SS dry eye patients was performed for the quantification of HLA-DR surface expression. With a conjunctival epithelial cell line (ChWK), HLA-DR regulation by various cytokines was evaluated, and confocal immunocytochemical and western blot analyses were performed to evaluate the activation of nuclear factorkappa B (NF-kappaB) and signal transducers and activators of transcription 1 and 3 (STAT1 and STAT3, respectively). RESULTS: HLA-DR expression was upregulated in conjunctival epithelial cells of SS patients but not in non-SS dry eye patient or healthy control subject. IFN-gamma was the only cytokine that effectively upregulated HLA-DR expression in ChWK, which was synergistically enhanced by tumor necrosis factor-alpha (TNF-alpha). IFN-gamma induced the nuclear translocation of NF-kappaB, but did not activate STAT1 or STAT3 in ChWK. CONCLUSIONS: Upregulation of HLA-DR antigen in the conjunctival epithelium of SS patients may be regulated by IFN-gamma through the activation of NF-kappaB.

Adult↗
PubMed1998

Construction, propagation, and titer estimation of recombinant adenoviruses carrying proapoptotic genes.

Generation of a recombinant adenovirus (Adv) that induces the constitutive expression of an apoptotic gene has been extremely difficult owing to severe apoptotic damage to the host cell. In this study, 293 cells were transduced with the caspase-inhibiting CrmA gene (293-CrmA cells), and used as host cells to generate Adv carrying apoptosis-inducing genes (proapoptotic genes). The 293-CrmA cells proved to be highly efficient for the construction of recombinant Adv carrying genes encoding Fas and Fas ligand. Moreover, the 293-CrmA line produced an ample quantity of these recombinant viruses. Because the conventional 293 plaque formation assay did not reflect the actual number of cells infected with the Adv carrying the proapoptotic gene, a determination of the Adv DNA copy number introduced into target cells was necessary to evaluate the quantity of infective virus. The techniques described here should be widely applicable for the construction of a recombinant Adv, in ample quantity, and for the estimation of the quantity of recombinant Adv produced.

Adenoviridae↗
PubMed1998

Local expression of immunoregulatory IL-12p40 gene prolonged syngeneic islet graft survival in diabetic NOD mice.

Local production of immunosuppressive cytokines will be one of the most suitable therapeutic strategies against organ-specific autoimmune diabetes. To establish such a new therapy, we constructed recombinant adenoviral vectors with inserted mIL-12p40 (Ad.IL-12p40) and mIL-10 (Ad.IL-10). Sufficient amounts of IL-12p40 and IL-10 were secreted by relevant adenovirus-transfected nonobese diabetic (NOD) islets. Shortly after transfection, 400 NOD islets transfected with Ad.IL-12p40 or Ad.IL-10 were transplanted under the renal capsule of a newly diabetic NOD mouse. NOD mice with IL-12p40-producing islet grafts kept normoglycemia in all of 14 grafted mice for over 4 wk after transplantation. In contrast, NOD mice with IL-10-producing islet grafts became diabetic in all of six grafted mice within 2 wk af-ter transplantation. Reverse transcription-PCR analysis revealed that local production of IL-12p40 led to the decrease of interferon-gamma and the augmentation of transforming growth factor-beta at the graft site. These results suggest that IL-12 plays an important role in the destruction of islet cells at the inflamed site of autoimmunity. Such a local blockade of IL-12 would be a useful gene therapy for human autoimmune diabetes.

Adenoviridae↗
PubMed1998

A human liver cell line exhibits efficient translation of HCV RNAs produced by a recombinant adenovirus expressing T7 RNA polymerase.

An in vitro system that supports the efficient growth of hepatitis C virus (HCV) and reflects its complete in vitro replication cycle has not yet been established. The establishment of a minigene RNA of HCV in mammalian cells could facilitate the study of virus-cell interactions and the molecular pathogenesis of this virus. We constructed a replication-deficient recombinant adenovirus expressing bacteriophage T7 RNA polymerase under the control of CAG promoter (AdexCAT7). A high level of T7 RNA polymerase was detectable for at least 11 days after inoculation. Cells infected with AdexCAT7 were then transfected with plasmids carrying the authentic T7 promoter, the 5' untranslated region (UTR) of encephalomyocarditis virus, a luciferase gene, and a T7 terminator (pT7EMCVLuc) or carrying the modified T7 promoter, the 5'UTR of HCV, a luciferase gene, the coding region of C-terminal of NS5B and the 3'UTR of HCV, a ribozyme of hepatitis D virus and a T7 terminator (pT7HCVLuc). Most of the cell lines examined supported a higher expression of luciferase by transfection with pT7EMCVLuc than with pT7HCVLuc. However, one cell line, FLC4, derived from a human hepatocellular carcinoma, exhibited very high reporter gene expression with pT7HCVLuc. In this cell line, transfection with RNA synthesized in vitro from pT7HCVLuc induced a higher level of reporter gene expression than RNA from pT7EMCVLuc. The T7-adenovirus system for the synthesis of HCV minigenes in vivo provides useful information on the molecular mechanisms of HCV translation in human liver cells.

3' Untranslated Regions↗
PubMed1998

Role of nucleotide sequences of loxP spacer region in Cre-mediated recombination.

The Cre recombinase mediates precise site-specific recombination between a pair of loxP sequences through an intermediate containing Holiday junction. The recombination junction in the loxP sequence is located within the asymmetric 8-nucleotide spacer region. To examine the role of each nucleotide sequence of the spacer region in the recombination process, we synthesized a complete set of 24 loxP spacer mutants with single-base substitutions and 30 loxP spacer mutants with double-base substitutions. Each synthesized loxP mutant was ligated at both ends of a linear DNA or to one end of a DNA-containing wild-type loxP at the other end and their recombination efficiencies were analyzed with an in vitro system. The sequence identity of the right two nucleotides and left four nucleotides in the central six bases of the spacer region was found to be essential for formation and resolution, respectively, of the intermediate product. Furthermore, even when homology was maintained, the recombination efficiencies were lower than that of wild-type loxP and varied among mutants. Based on this knowledge, we identified two loxP mutants with double-base substitutions, mutants 5171 and 2272, which recombine efficiently with an identical mutant but not with the other mutant or wild-type loxP.

Base Sequence↗