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Biomedical subjects

I Sakai

Publications and source records attributed to I Sakai.

At least 37 records · Page 2Linked to original sources
PubMed2001

Presence of aldose reductase inhibitors in tea leaves.

Water extract from commercial English tea has a potent inhibitory activity against human placenta aldose reductase (NADPH oxidoreductase, E.C.1.1.1.21.). Inhibitory activity was separated into five major fractions by one-step chromatography with a C-18 reverse phase column. The most active fraction was further subjected to reverse phase column chromatography. As a result, a well-known flavone-glycoside, isoquercitrin, was isolated as the most potent chemical. The inhibitory character of isoquercitrin for aldose reductase was a mix of uncompetitive and noncompetitive inhibitions, and its IC50 was 1 x 10(-6) M. In rat sciatic nerve tissue preparations, sorbitol accumulation in the presence of high concentrations of glucose (30 mM) was inhibited by 38% at 5 x 10(-4) M of isoquercitrin. The flavone-glycoside isoquercitrin is the active inhibitor of aldose reductase inhibitor present in English tea. Given the ability of aldose reductase inhibitors to prevent diabetic complications, an epidemiological study of the effect of tea consumption on the pathogenesis and progression of diabetic complications would be interesting.

Aldehyde Reductase↗
PubMed2001

Development of interferon-alpha resistant subline from human chronic myelogenous leukemia cell line KT-1.

OBJECTIVE: Interferon-alpha (IFN-alpha) is one of the most effective therapeutic agents for a number of hematological malignancies, including chronic myelogenous leukemia (CML). Nevertheless, its efficacy is limited because of the development of resistance to IFN-alpha therapy. Previously, we established the novel human CML cell line KT-1, which is sensitive to the antiproliferative effects of IFN-alpha. Here, we report the establishment of an IFN-alpha-resistant subline, KT-1/A3R alpha 1000, by culturing KT-1/A3 cells (IFN-alpha-sensitive subline of KT-1) with increasing concentrations of IFN-alpha, in order to analyze the mechanism of acquisition of IFN-alpha resistance in CML cells after IFN-alpha therapy. SUBJECTS AND METHODS: We developed an IFN-alpha-resistant tumor cell variant, KT-1/A3R alpha 1000, from the KT-1/A3 cell line by culturing cells with increasing concentrations of IFN-alpha. This subline was examined for its ability to proliferate and its resistance to apoptosis in high concentrations of IFN-alpha. The induction of the ISGF3 complex in response to IFN-alpha alpha in KT-1/A3R alpha 1000 was compared with that in the parental cell. RESULTS: The levels of interferon-stimulated gene factor 3 components (STAT1, STAT2, and p48) proteins and STAT2 tyrosine phosphorylation induced after IFN-alpha treatment were unchanged, but formation of the ISGF3 complex was remarkably reduced in KT-1/A3R alpha 1000 cells compared to parental cells. CONCLUSION: The KT-1/A3R alpha 1000 subline is a useful model for studying the mechanism of IFN-alpha resistance after IFN-alpha therapy.

Antineoplastic Agents↗
PubMed2001

[Early detection of hypoxia with BIS monitoring during percutaneous cardiopulmonary support].

We report a patient in whom hypoxia developed during percutaneous cardiopulmonary bypass (PCPS) and was detected with the lowering of the bispectral index (BIS) values. A 7-yr-old boy was managed with PCPS for the treatment of cardiogenic shock after cardiac surgery. His circulation was dependent on PCPS and pulse pressure was nearly zero. Signals by pulse oxymetry were undetectable and periodical blood gas analysis was performed to confirm proper oxygenation. BIS was monitored, and a gradual decrease in the value was observed. Careful observation also revealed darkening of the blood in the PCPS circuit and blood gas analysis showed severe hypoxia. Oxygen concentration of the gas to a PCPS oxygenator was increased immediately and new PCPS circuit was prepared. It took almost two minutes to exchange the circuit. Near circulatory arrest might have occurred during the procedure and BIS and suppression ratio (SR) became below 10 and above 90, respectively. Both returned to the previous values 30 min after the replacement of the circuit. Severe hypoxia, otherwise overlooked, was detected with BIS monitoring and BIS reflected the circulatory status of the patient, especially of the brain. This monitoring is useful to confirm proper oxygenation during PCPS.

Cardiopulmonary Bypass↗
PubMed2001

[A case of polyarteritis nodosa limited to both calves with a low titer of MPO-ANCA].

A-57-year-old woman had suffered from high fever, general malaise, and loss of weight (6 kg) since January, 2000. She was admitted to our hospital in May, 2000, because of gait disturbance following to swelling of bilateral calves with severe pain beside the above symptoms. Laboratory data showed leukocytosis (WBC 10,000/microliter), high ESR (98 mm/hr), positive CRP (3.43 mg/dl), positive ANA (x160), high titer of RA (266 IU/l), and a low titer of MPO-ANCA (18 EU). T 2-weighted magnetic resonance image (MRI) showed intensity area of the M. gastrocnemius. Skin biopsy specimens of the right leg demonstrated necrotizing arteritis of small-sized arteries. These findings supported the diagnosis of limited type of polyarteritis nodosa (PN). In this report, we demonstrate a rare case of PN limited to both calves with characteristic MRI findings and a low titer of MPO-ANCA.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2000

The initial distribution volume of glucose rather than indocyanine green derived plasma volume is correlated with cardiac output following major surgery.

OBJECTIVES: To determine whether the initial distribution volume of glucose (IDVG) rather than plasma volume or blood volume is correlated better with cardiac output during the 4 days following major surgery. DESIGN AND SETTING: Prospective clinical investigation in the general intensive care unit of a university hospital. PATIENTS AND METHODS: 31 consecutive patients who underwent radical surgery for esophageal carcinoma were enrolled. Continuous thermodilution cardiac output monitor was placed in the operating room. Indocyanine green (ICG; 25 mg) and glucose (5 g) were administered simultaneously to calculate IDVG and plasma volume determined using the ICG dilution method. Blood volume was also calculated from plasma volume ICG and hematocrit. Those volumes were measured on admission to the ICU and daily on the first 3 postoperative days. The relationships between each volume and cardiac index (CI), and between routine clinical variables and CI were evaluated. RESULTS: IDVG had a linear correlation with CI in the early postoperative days (r = 0.71, n = 124, p < 0.000001). Measurements of neither the plasma volume nor the blood volume yielded a better correlation with CI than did IDVG (r = 0.45, n = 124, p < 0.000001, and r = 0.23, n = 124, p < 0.01, respectively). No correlation was found between pulmonary artery wedge pressure and CI or between central venous pressure and CI. CONCLUSIONS: Our results indicate that IDVG rather than intravascular volume is correlated with cardiac output. We suggest that IDVG has potential as an alternative indicator of cardiac preload following major surgery.

Adult↗
PubMed2000

Sensitivity to interferon-alpha and interferon-stimulated gene factor 3 binding activity in human chronic myelogenous leukemia cell line KT-1.

The mechanism of responsiveness of chronic myelogenous leukemia (CML) cells to interferon (IFN)-alpha was examined by using two subclones of CML cell line KT-1 which exhibited significantly different sensitivities to the antiproliferative and apoptosis-inducing effects of IFN-alpha. IFN-stimulated gene factor 3 (ISGF3) formation by IFN-alpha was reduced in the IFN-alpha-resistant subclone compared to the IFN-alpha-sensitive subclone. We conclude that the level of ISGF3 formation is responsible for the difference in IFN-alpha responses between these subclones.

Antineoplastic Agents↗
PubMed2000

[Subcutaneous panniculitic T-cell lymphoma with chromosomal abnormalities and large granular lymphocytes morphology].

A 72-year-old woman was admitted because of a subcutaneous hip tumor. A biopsy specimen of the tumor showed a mixture of medium-sized and large lymphocytes infiltrating the subcutaneous fat tissue with a lobular panniculitis-like pattern--a histologic feature of subcutaneous panniculitic T-cell lymphoma (SPTCL). May-Grünwald-Giemsa-stained cytospin slides of freshly isolated neoplastic cell explants showed that the cells had the characteristics of large granular lymphocytes. Immunophenotypic analysis showed that the cells expressed CD56--a natural killer-associated antigen--as well as the cytotoxic T-cell phenotype CD3+ CD4- CD8+. Southern blot analysis revealed rearrangement bands of the TCR-beta chain gene. Chromosome analysis showed complex abnormalities including t(1;6) (q11; p21). The present case may shed some light on the origin and pathogenesis of SPTCL.

Aged↗
PubMed1999

Galectin-1 regulates initial axonal growth in peripheral nerves after axotomy.

The signals that prompt the axons to send out processes in peripheral nerves after axotomy are not well understood. Here, we report that galectin-1 can play an important role in this initial stage. We developed an in vitro nerve regeneration model that allows us to monitor the initial axon and support cell outgrowth from the proximal nerve stump, which is comparable to the initial stages of nerve repair. We isolated a factor secreted from COS1 cells that enhanced axonal regeneration, and we identified the factor as galectin-1. Recombinant human galectin-1 (rhGAL-1) showed the same activity at low concentrations (50 pg/ml) that are two orders of magnitude lower than those of lectin activity. A similarly low concentration was also effective in in vivo experiments of axonal regeneration with migrating reactive Schwann cells to a grafted silicone tube after transection of adult rat peripheral nerve. Moreover, the application of functional anti-rhGAL-1 antibody strongly inhibited the regeneration in vivo as well as in vitro. The same effect of rhGAL-1 was confirmed in crush/freeze experiments of the adult mouse sciatic nerve. Because galectin-1 is expressed in the regenerating sciatic nerves as well as in both sensory neurons and motor neurons, we suggest that galectin-1 may regulate initial repair after axotomy. This high activity of the factor applied under nonreducing conditions suggests that galectin-1 may work as a cytokine, not as a lectin.

Animals↗
PubMed1999

Down-regulation of CXCR4 by human herpesvirus 6 (HHV-6) and HHV-7.

Recent studies have demonstrated that human herpesvirus 6 (HHV-6) and HHV-7 interact with HIV-1 and alter the expression of various surface molecules and functions of T lymphocytes. The present study was undertaken to clarify whether coreceptors for HIV-1, CXCR4 and CCR5, are necessary for HHV-6 and HHV-7 infection. Although CXCR4 and CCR5 appeared not to be the coreceptors for these viruses, marked down-regulation of CXCR4, but not CCR5, was detected in HHV-6 variant A (HHV-6A)-, HHV-6 variant B (HHV-6B)-, and HHV-7-infected cells. Down-regulation of CXCR4 resulted in impairment of chemotaxis and a decreased level of elevation of the intracellular Ca2+ concentration in response to stromal cell-derived factor-1. Northern blot analysis of mRNAs extracted from HHV-6A-, HHV-6B-, and HHV-7-infected CD4+ T lymphocytes demonstrated a markedly decreased level of CXCR4 gene transcription, but the posttranscriptional stability of CXCR4 mRNA was not significantly altered. These data demonstrate that unlike HIV-1, HHV-6 and HHV-7 infections do not require expression of CXCR4 or CCR5, whereas marked down-regulation of CXCR4 is induced by these viruses, suggesting that HHV-6 and HHV-7 infections may render CD4+ T lymphocytes resistant to T lymphocyte-tropic HIV-1 infection.

Antibodies, Monoclonal↗
PubMed1999

[Isolation of type-A blood group active glycoproteins from salivas and their reaction with monoclonal antibodies].

We have previously examined several ABO blood grouping antibodies with whole saliva and observed that there were two types of antibodies. One group of antibodies reacted with both secretory and non-secretory saliva, and the other with only secretory saliva. In order to clarify the differences in reaction of the antibodies with saliva, we needed to analyze of antigens in secretory and non-secretory saliva. Therefore, we prepared blood group active glycoproteins from secretory and non-secretory saliva by affinity chromatography and gel filtration. The secretory saliva gave three active peaks, one large peak in the void volume and two small peaks in fractions of smaller molecular weights on Sepharose-CL6B after the affinity chromatography. From the non-secretory saliva, a single active peak in the void volume, which corresponded to the major peak in the secretory saliva, was found. Most blood group activities were found in those void volume fractions. Moreover, capillary electrophoresis showed that these blood group active glycoproteins were identical, and that there were immunological differences between secretory and non-secretory salivary blood group substances.

ABO Blood-Group System↗
PubMed1998

Ratio of indocyanine green and glucose dilutions detects capillary protein leakage following endotoxin injection in dogs.

This study was designed to determine whether endotoxin-induced generalized capillary protein leakage can be detected using the ratio of indocyanine green (ICG) and glucose dilutions. Plasma volume determined by the ICG dilution method (Vd-ICG) and the initial distribution volume of glucose (IDVG) were assessed simultaneously before and after either the administration of lipopolysaccharide (LPS) 0.3 mg kg-1 or equal amounts of isotonic saline in two groups of eight dogs, using a one-compartment model after simultaneous infusions of both ICG 0.5 mg kg-1 and glucose 100 mg kg-1. The IDVG has been shown to indicate the extracellular fluid volume of highly perfused organs including plasma. All post-treatment values decreased compared with the pre-treatment values (P < 0.05), except Vd-ICG in the LPS group, even though the post-treatment total plasma protein concentration of the LPS group decreased significantly compared with the pre-treatment value (P < 0.05). The post-treatment Vd-ICG/IDVG ratio of the saline group remained unchanged compared with that of the pre-treatment, and the post-treatment ratio of the LPS group increased significantly (P < 0.01). It can be concluded that overestimation of the Vd-ICG can occur after endotoxin injection, which can be detected by simultaneous measurements of the Vd-ICG and the IDVG.

Animals↗
PubMed1998

Relation of serum total cholesterol, serum triglycerides and fasting plasma glucose to colorectal carcinoma in situ.

BACKGROUND: No one has previously examined the relation of serum total cholesterol, serum triglycerides and fasting plasma glucose to colorectal carcinoma in situ. METHODS: A case-control study was performed with 129 cases of colorectal carcinoma in situ and 258 matched controls among examinees undergoing a health check-up in Tokyo from January 1991 to March 1993. RESULTS: There was a significant, positive association between serum total cholesterol levels and the risk of colorectal carcinoma in situ after adjustment for age, sex, body mass index, smoking status and alcohol consumption. Serum triglyceride levels were significantly and positively associated with colorectal carcinoma in situ risk regardless of adjustment for the above covariates. Although there was no clear relation between colorectal carcinoma in situ and fasting plasma glucose levels, a modest increase of colorectal carcinoma in situ risk was observed in the highest category (> or =116 mg/dl) of fasting plasma glucose levels. CONCLUSIONS: The findings suggest a positive association between serum total cholesterol levels and the risk of colorectal cancer, rather than an inverse relation. The strong association with serum triglyceride levels and the weak association with fasting plasma glucose levels support the hypothesis that hyperinsulinaemia may play an important role in colorectal carcinogenesis.

Adult↗
PubMed1998

Measurements of extracellular fluid volume in highly perfused organs and lung water in hypo- and hypervolaemic dogs.

The purpose of this study was to identify whether the central extracellular fluid volume status following hypo- and hypervolaemia can be measured by the initial distribution volume of glucose or by the extravascular lung water. These two estimates were compared with the initial distribution volume of sucrose which has been used as an indicator for the measurement of the extracellular fluid volume. The above three estimates were determined by the administration of glucose, chilled saline and sucrose solutions, before and after haemorrhage (30 mL kg-1), and subsequent fluid load (lactated Ringer's solution 90 mL kg-1). The distribution volumes of glucose and sucrose decreased after haemorrhage and increased after fluid load compared with normovolaemic values, and a linear correlation was obtained between these two distribution volumes (r = 0.93, P < 0.001, n = 36). However, the extravascular lung water remained statistically unchanged throughout the procedure, despite a weak linear correlation with the sucrose distribution volume (r = 0.38, n = 33, P < 0.05). These results indicate that the initial distribution volume of glucose is more useful as an indicator of the central extracellular fluid volume status than the extravascular lung water.

Animals↗
PubMed1997

IL-1 beta enhances neurite regeneration from transected-nerve terminals of adult rat DRG.

We clarified the roles of IL-1 beta in peripheral neural regeneration after axotomy in a three-dimensional collagen gel culture system ranging from a single neurone to a dorsal root ganglion (DRG) explant with its associated nerve bundles. Application of 30 U/ml IL-1 beta to the culture systems clearly enhanced neural regeneration. This regeneration was evident in transected nerve terminals of DRG explants with or without associated nerve bundles, but not in dissociated single neurones. Neural survival was not affected by IL-1 beta in any of these culture systems. These results suggest that IL-1 beta stimulates surrounding non-neuronal cells to secrete neurotrophic factors, thus enhancing neurite regeneration from transected nerve terminals in cultured adult DRG explants.

Animals↗
PubMed1997

The kinase domain of Jak2 mediates induction of bcl-2 and delays cell death in hematopoietic cells.

Granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-3, and IL-5 stimulate DNA synthesis and proliferation and inhibit apoptosis in hematopoietic cells. Multiple signal pathways are activated by binding of these ligands to their receptors, which share a common beta subunit. Janus protein kinase 2 (Jak2) binds to the membrane proximal domain of the beta chain and is phosphorylated on receptor ligation. To explore the role of Jak2 in the regulation of specific signal transduction pathways, we constructed fusion proteins with a CD16 external domain, a CD7 transmembrane region, and a Jak2 cytoplasmic domain. This cytoplasmic domain consisted either of wild type Jak2 (CD16/Jak2-W) or Jak2 mutations with deletions of (a) the amino terminus (CD16/Jak2-N), (b) kinase-like domain (CD16/Jak2-B), (c) kinase domain (CD16/Jak2-C), or (d) amino-terminal and kinase-like domains, leaving the kinase domain (CD16/Jak-K) intact. In contrast to the CD16/Jak2-W fusion protein, which requires cross-linking for activation, CD16/Jak2-N, CD16/Jak2-B, and CD16/Jak2-K were constitutively phosphorylated, and they stimulated Shc phosphorylation and increased binding of STAT to DNA in Ba/F3 cells. Cell lines derived from IL-3-dependent Ba/F3 cells stably transfected with CD16/Jak2-W, CD16/Jak2-N, or CD16/Jak2-B mammalian expression vectors died at a rate similar to that of the parental cells on IL-3 deprivation. In contrast, CD16/Jak2-K cell lines exhibited increased expression of bcl-2 and pim-1 mRNA and maintained their viability when compared with control cell lines. Thus, activation of tyrosine phosphorylation by creating a CD16/Jak2-K fusion is sufficient to activate pathways that prevent cell death.

Antigens, CD7↗
PubMed1997

Case-control study of colorectal carcinoma in situ and cancer in relation to cigarette smoking and alcohol use (Japan).

A case-control study was performed in order to examine the relation of cigarette smoking and alcohol use to colorectal carcinoma in situ and cancer, separately. Study subjects consisted of 129 colorectal carcinoma in situ cases, 66 colorectal cancer cases, and 390 controls recruited from health check-up examinees in Tokyo from January 1991 to March 1993. Smoking status and alcohol habit were ascertained from a self-administered questionnaire. Both cumulative cigarette smoking and current smoking status were associated significantly with an increased risk of carcinoma in situ. A statistically nonsignificant increase in the risk of colorectal cancer was noted only among those with the heaviest exposure category of these measures of smoking. The cumulative exposure to cigarette smoking within recent 20 years was associated significantly with an increased risk of carcinoma in situ, whereas smoking until 20 years before the diagnosis was associated significantly with an increase of cancer risk. A significant and positive association was observed between cumulative alcohol drinking and colorectal cancer. These findings suggest that cigarette smoking may act as an initiator in colorectal carcinogenesis and also provide weak evidence that alcohol drinking is related to an increased risk of colorectal cancer.

Adenoma↗