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D Sasaki

Publications and source records attributed to D Sasaki.

At least 19 recordsLinked to original sources
PubMed2006

Changes in bacterial community during fermentative hydrogen and acid production from organic waste by thermophilic anaerobic microflora.

AIMS: Changes in fermentation pattern during the treatment of organic wastes containing solid materials by thermophilic anaerobic microflora were investigated with respect to product formation and bacterial community structure during hydrogen production. METHODS AND RESULTS: Anaerobic microflora enriched from sludge compost was cultivated using artificial garbage slurry in a continuous flow-stirred tank reactor. Product formation varied depending on pH and hydraulic retention time (HRT) applied. Community analysis by terminal restriction fragment length polymorphism and clone library analysis of polymerase chain reaction-amplified bacterial 16S rDNA indicated that difference in the fermentative product distribution could be caused by different populations of micro-organisms in the microflora. CONCLUSION: Hydrogen fermentation with acetate/butyrate formation was optimized at <1.0 d HRT at pH 5.0 and 6.0. Thermoanaerobacterium thermosaccharolyticum was the dominant hydrogen-producing micro-organism. Conversely, unidentified organisms became dominant after 4.0 d HRT at pH 7.0 and 8.0, where relatively high-solubilization efficiency of solid materials was observed with no production of hydrogen. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report describing product formation in the fermentation of solid organic wastes by a mixed population of micro-organisms. Various fermentation patterns including hydrogen fermentation were characterized and evaluated from engineering and microbial aspects.

Acids↗
PubMed2005

Ossification of the Achilles tendon--a case report.

Ossification of the Achilles tendon is a very unusual condition. We report a case with bilateral Achilles tendon ossification followed up for twelve years, treated twice surgically on the left side and conservatively on the right side. At the age of 51, the patient's plain radiogram showed bilateral ossifications of the Achilles tendon (right 55 mm, left 15 mm in length). The left side small mass was removed. The right side mass was decided to be followed up because of its large size. At the age of 61, ossification recurred on the left side. Conservative treatment with etidronate disodium for two years failed to prevent ossification from progressing. At the age of 63, the mass on the right and left sides increased to 70 mm and 45 mm in length, respectively. The mass of the left side was excised again, and dull pain disappeared postoperatively on the left side.

Achilles Tendon↗
PubMed2001

Length dependence of tension generation in rat skinned cardiac muscle: role of titin in the Frank-Starling mechanism of the heart.

BACKGROUND: At the basis of the Frank-Starling mechanism is the intrinsic ability of cardiac muscle to produce active tension in response to stretch. Titin, a giant filamentous molecule involved in passive tension development, is intimately associated with the thick filament in the sarcomere. Titin may therefore contribute to active tension development by modulating the thick filament structure when the muscle is elongated. METHODS AND RESULTS: Rat skinned right ventricular trabeculae were used. Passive tension at a sarcomere length (SL) of 2.0 to 2.4 micrometer was decreased after treatment of the preparation with trypsin (0.25 microgram/mL) for 13 minutes in the relaxed state at 20 degrees C. This mild trypsin treatment degraded titin without affecting other major contractile proteins. The sarcomere structure was little affected by brief contractions in the trypsin-treated preparations. When SL was adjusted to the slack SL (1.9 micrometer), active tension was unaffected by trypsin under partial (pCa 5.55) and maximal (pCa 4.8) activation. At longer SLs, however, active tension was significantly (P<0.01) decreased after trypsin treatment at either pCa. The increase in active tension on reduction of interfilament lattice spacing, produced by dextran T-500 (molecular weight approximately 500 000), was not influenced by trypsin (SL 1.9 micrometer). In trypsin-treated preparations, the increase in active tension as a function of muscle diameter was nearly the same for lengthening and osmotic compression at the slack SL. CONCLUSIONS: The length-dependent activation in cardiac muscle, an underlying mechanism of the Frank-Starling law of the heart, is at the myofilament level, predominantly modulated by titin and interfilament lattice spacing changes.

Animals↗
PubMed2001

Acidosis or inorganic phosphate enhances the length dependence of tension in rat skinned cardiac muscle.

1. We investigated the effect of acidosis on the sarcomere length (SL) dependence of tension generation, in comparison with the effect of inorganic phosphate (P(i)), in rat skinned ventricular trabeculae. The shift of the mid-point of the pCa-tension relationship associated with an increase in SL from 1.9 to 2.3 microm (DeltapCa(50)) was studied. 2. Decreasing pH from 7.0 to 6.2 lowered maximal and submaximal Ca(2+)-activated tension and increased DeltapCa(50) in a pH-dependent manner (from 0.21 +/- 0.01 to 0.30 +/- 0.01 pCa units). The addition of P(i) (20 mM) decreased maximal tension and enhanced the SL dependence, both to a similar degree as observed when decreasing pH to 6.2 (DeltapCa(50) increased from 0.20 +/- 0.01 to 0.29 +/- 0.01 pCa units). 3. Further experiments were performed using 6 % (w/v) Dextran T-500 (molecular weight approximately 500 000) to osmotically reduce interfilament lattice spacing (SL, 1.9 microm). Compared with that at pH 7.0, in the absence of P(i) the increase in the Ca(2+) sensitivity of tension induced by osmotic compression was enhanced at pH 6.2 (0.18 +/- 0.01 vs. 0.25 +/- 0.01 pCa units) or in the presence of 20 mM P(i) (0.17 +/- 0.01 vs. 0.24 +/- 0.01 pCa units). 4. H(+), as well as P(i), has been reported to decrease the number of strongly binding cross-bridges, which reduces the co-operative activation of the thin filament and increases the pool of detached cross-bridges available for interaction with actin. It is therefore considered that during acidosis, the degree of increase in the number of force-generating cross-bridges upon reduction of interfilament lattice spacing is enhanced, resulting in greater SL dependence of tension generation. 5. Our results suggest that the Frank-Starling mechanism may be enhanced when tension development is suppressed due to increased H(+) and/or P(i) under conditions of myocardial ischaemia or hypoxia.

Acidosis↗
PubMed2001

Reactions of PhSCH(2)Li and NCCH(2)Li with benzaldehyde and benzophenone: when does the mechanism change from ET to polar?

The carbonyl-carbon kinetic isotope effect (KIE) and the substituent effect were measured for the reaction of phenylthiomethyllithium (PhSCH(2)Li, 1) with benzaldehyde and benzophenone, and cyanomethyllithium (NCCH(2)Li, 2) with benzaldehyde, and the results were compared with those for other lithium reagents such as MeLi, PhLi, CH(2)=CHCH(2)Li, and CH(2)=C(OLi)C(CH(3))(3). It was previously shown that the reactions of MeLi, PhLi, and CH(2)=CHCH(2)Li proceed via a rate-determining electron transfer (ET) process whereas the reaction of lithium pinacolone enolate goes through the polar (PL) mechanism. The reaction of 1 with benzaldehyde gave no carbonyl-carbon KIE ((12)k/(13)k = 0.999 +/- 0.004), similar to that measured previously for the MeLi reaction with benzophenone ((12)k/(14)k = 1.000). The effect of substituents of the aromatic ring of benzaldehyde and benzophenone on the reactivity gave very small Hammett rho values of 0.17 +/- 0.03 and 0.26 +/- 0.05, respectively. These small rho values are again similar to that observed for the reaction of MeLi. Likewise the reactions of 2 with benzaldehydes gave small KIE and the rho value ((12)k/(13)k = 0.996 +/- 0.004, rho = 0.14 +/- 0.02). Dehalogenation and enone-isomerization probe experiments for 2 showed no evidence for the presence of radical-ion pair of sufficient lifetime during the course of the reaction. It is concluded that the reactions of 1 and 2 with the aromatic carbonyl compounds proceed via the electron transfer-radical coupling mechanism with rate-determining ET as in the reactions of MeLi, PhLi, and CH(2)=CHCH(2)Li.

Journal Article↗
PubMed2001

Changes in intraluminal pressure in rat large intestines with aging and effects of dietary fiber.

Changes in intraluminal pressure in rat colon with aging and with the effects of dietary fiber were measured. A pressure sensor was inserted into the rat large intestine under endoscopic guidance. The intraluminal pressure curve in the colon was recorded, and the motility index was calculated by this curve. The rats were divided into three groups with a fiber-free diet, a cellulose diet (10% w/w), or a pectin diet (10% w/w). Intraluminal pressure was measured in the proximal, middle, and distal colon at 2, 4, 8, 12, and 16 months after birth. Intraluminal pressure in three sites increased with age and decreased in the latter half of the study. The motility index was lower during the course in the fiber groups, especially the pectin group more than the nonfiber group. This result suggests that long-term ingestion of dietary fiber might have a prophylactic effect on the development of diverticula.

Age Factors↗
PubMed2001

Lateral-flow assay for rapid serodiagnosis of human leptospirosis.

An assay device for the rapid detection of Leptospira-specific immunoglobulin M (IgM) antibodies in human sera is presented. The sensitivity (85.8%) and specificity (93.6%) of the assay compared well (91.9% agreement) with those of an IgM enzyme-linked immunosorbent assay routinely used in the serodiagnosis of leptospirosis. The sensitivity of the assay varied with the stage of the disease. The assay uses stabilized components and is simply performed by the addition of serum and sample fluid to the sample well of the assay device. The assay is read after 10 min, and a positive result is obtained when staining of the test line is observed.

Antibodies, Bacterial↗
PubMed1997

The unexpected G0/G1 cell cycle status of mobilized hematopoietic stem cells from peripheral blood.

Treatment with a combination of cytokines and chemotherapy can effectively stimulate the release of hematopoietic stem cells (HSC) into the peripheral blood (PB), which can then be harvested for transplantation. The cell cycle status of the harvested HSC from mobilized PB (MPB) is of interest because of the impact that cell cycling may have on optimizing the conditions for ex vivo expansion, retrovirus-mediated gene transfer, and the engraftment of transplanted tissues. Therefore, we characterized the cell cycling status of mobilized HSC from mice and humans. The murine HSC, which express the phenotype c-kit+ Thy-1.1lo Lin-/lo Sca-1+, were purified from PB, bone marrow (BM), and spleen after the mice were treated with the mobilizing regimen of granulocyte colony-stimulating factor (G-CSF) or a combination of cyclophosphamide (CTX) and G-CSF. Human HSC (CD34+ Thy-1+ Lin-) and progenitor cells (CD34+ Thy-1-Lin-) were isolated from the BM of untreated healthy volunteers and from MPB of healthy volunteers and patients treated with G-CSF or a combination of CTX and GM-CSF. Cell cycle status was determined by quantitating the amount of DNA in the purified cells after staining with the dye Hoechst 33342. Fluorescence-activated cell sorting analysis of the progenitor cells from the murine and human samples showed an unexpected finding, ie, virtually none of the cells from the MPB was cycling. The G0/G1 status of HSC from MPB was surprising, because a significant proportion of HSC from BM are actively proliferating and, after mobilization, the HSC in the spleen and BM were also actively cycling.

Animals↗
PubMed1996

Fluorescence signaling of ligand binding and assembly in metal-chelating lipid membranes.

BACKGROUND: Chemical information is sometimes transmitted across cell membranes by ligand-induced assembly of receptors. We have previously designed a series of lipids with metal-chelating headgroups that can serve as general receptors for proteins containing accessible histidines. Such lipids can also be derivatized with pyrene, a fluorescent probe that has a different emission maximum when it is aggregated (excimer fluorescence) from that seen for the monomer. We set out to examine whether lipids of this kind would produce a signal in response to ligand binding. RESULTS: A model ligand, poly-L-histidine (poly(His)), bound specifically to pyrene-labeled Cu(II)-iminodiacetate lipid (Cu-PSIDA) within a membrane matrix. Binding of poly(His) induces the redistribution of Cu-PSIDA, so that it forms pyrene-rich domains that are detectable by the increased ratio of excimer to monomer fluorescence. Using rhodamine-labeled poly(His), we have shown that the receptor lipid domains correspond to poly(His)-rich domains below the lipid interface. CONCLUSIONS: The Cu-PSIDA receptor signals binding of the macromolecular ligand through its excimer fluorescence and allows the resulting domains formed by ligand assembly to be imaged. Fluorescent Cu-PSIDA can thus serve as an optical reporter of ligand-induced lipid reorganization.

Chelating Agents↗
PubMed1995

Cytokine-mobilized peripheral blood CD34+Thy-1+Lin- human hematopoietic stem cells as target cells for transplantation-based gene therapy.

Gene-therapy of blood-borne disorders may be best achieved using hematopoietic stem cells (HSC) which have extensive self renewal potential as well as multilineage repopulating potential as a cellular target. The human HSC, which is CD34+Thy-1+Lin- has been isolated from fetal, adult bone marrow and cytokine-mobilized peripheral blood (MPB) (1-3). Results presented in this study show that the degree of mobilization of HSC into peripheral blood of cancer patients is highly variable and that the combined use of high dose chemotherapy and GM-CSF as a mobilization strategy is superior to the use of G-CSF with regard to the mobilization of true HSC. A multistep cell isolation procedure has been developed which utilizes high speed flow-cytometric cell sorting and allows the isolation of sufficient numbers of HSC from MPB to permit their use as an hematopoietic graft for clinical transplantation. Hematopoietic stem cells isolated from MPB are capable of self-renewal and differentiation into multiple hematopoietic lineages as shown by their behavior in both in vitro and in vivo assays. Mobilized PB mononuclear cells isolated from cancer patients are frequently contaminated with tumor cells. Using this cell isolation procedure, HSC preparations from patients with multiple myeloma have been created with greatly reduced tumor cell burdens. These CD34+Thy-1+Lin- cells are capable of being stably transduced at high efficiency (32-75%) by co-culture on a cell line producing recombinant retroviruses containing the neomycin-resistant gene. These HSC cell populations are likely ideal targets for hematopoietic cell-based gene therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Clinical study of biological response modifiers as maintenance therapy for hepatocellular carcinoma.

We conducted a randomized, controlled trial comparing 5-fluorouracil (5-FU) with or without biological response modifiers (BRMs) as a maintenance therapy for hepatocellular carcinoma (HCC) after treatment with percutaneous ethanol injection (PEI), transcatheter arterial embolization (TAE) or arterial infusion of antitumor agents (AI). A total of 58 cases of HCC were classified into 4 groups as follows: group I, PSK with 5-FU (n = 15); group II, lentinan with 5-FU (n = 15); group III, OK-432 with 5-FU (n = 12); and group IV, 5-FU alone as the control (n = 16). The mean survival time, mortality rate, time to progression, and T4/T8 ratio of lymphocytes in the peripheral blood were compared among the four groups. There was no significant difference in the background factors among the groups. In group I, the T4/T8 ratio of lymphocytes was reduced after the therapy. No significant difference was found among the groups in terms of the mean survival time, mortality rate, or time to progression. PEI for initial therapy was superior to the other therapies in terms of the mean survival time and mortality rate. These results suggest that the addition of BRM to maintenance therapy with 5-FU exerts no prognostic benefit on HCC patients treated with PEI, TAE, or AI.

Aged↗
PubMed1994

Altered levels of prothymosin immunoreactive peptide, a growth-related gene product, during liver regeneration after chronic ethanol feeding.

Liver regeneration is regulated by the orderly activation of growth-related genes. Although ethanol impairs induction of liver regeneration by partial hepatectomy, we have not identified ethanol-associated differences in the hepatic mRNA levels of several proto-oncogenes, including c-myc, which peaks 3-6 hr post-partial hepatectomy. Prothymosin alpha, a gene encoding a ubiquitous nuclear protein, is activated by c-myc in resting fibroblasts and has been implicated as a regulator of cell proliferation. Prothymosin alpha mRNA levels reportedly increase 12-32 hr post-partial hepatectomy, several hours after c-myc induction. We sought to determine if chronic ethanol intake alters the expected induction post-partial hepatectomy of prothymosin alpha steady-state mRNA expression and protein levels. Comparing rats chronically fed ethanol with pair-fed controls, we found no significant differences in steady-state levels of prothymosin alpha mRNA; however, we did see a delay in the increase of prothymosin immunoreactive peptide in rats chronically fed alcohol. This suggests that the inhibition in protein levels in ethanol fed rats is not due to lower steady-state mRNA levels, but may occur post-transcriptionally. Further data are needed to determine if this finding is important in the inhibition in cell growth following partial hepatectomy in rats chronically fed ethanol.

Alcoholism↗
PubMed1994

Growth-inhibition by hemin in K562 human leukemic cells is related to hemoglobin-producing activity.

To determine the mechanism of the growth inhibition associated with the induction of erythroid differentiation in K562 cells by hemin, we used two K562 subclones with different hemoglobin (Hb)-producing activity. Hemin strongly inhibited the growth of K562-L, which had a low Hb-producing activity, but not that of K562-H, which had a high Hb-producing activity. When the cell growth of K562-L was inhibited by hemin, the S phase of the cell cycle decreased and the G2/M phase increased. In contrast, hemin had no effect on the cell cycle of K562-H. Without hemin treatment, the alpha-globin mRNA level was related to the degree of Hb production in K562-L and -H but the gamma-globin mRNA level was not. With hemin treatment, there was no increase in the alpha-globin mRNA level in K562-L but there was an increase in K562-H. The difference in alpha-globin mRNA levels correlated with the Hb production in K562-L and -H induced by hemin. The levels of c-myc and c-myb mRNAs in K562-L decreased when cell growth was strongly inhibited by hemin. These findings indicate that the growth inhibition of K562 cells by hemin is due to a suppression of the progression from the G0/G1 phase to the S phase and a delay in the G2/M phase, caused by the inhibition of c-myc and c-myb transcription. It is also affected by the Hb production, reflected in alpha-globin transcription.

Blotting, Northern↗
PubMed1993

Effect of 12-O-tetradecanoylphorbol-13-acetate on expression of cell surface antigens in two subclones of human leukemia K562 cells.

Two subclones (K562-L and -H) were previously isolated from K562 human leukemic cells according to hemoglobin production: K562-L was expressed in less than 5% and K562-H in more than 90% of dianisidine positive cells. 12-O-Tetradecanoylphorbol-13- acetate (TPA) suppressed the expression of the erythrocytic (glycophorin A) and myelocytic (CD11b) antigens in K562-L, but increased the expression of these antigens in K562-H. TPA increased the megakaryocytic (CD61) antigens in both cells. These findings suggest that there are distinct TPA responsible factors in K562-L and -H on the expression of the erythrocytic and myelocytic antigens.

Antigens, Surface↗
PubMed1993

Cloning and characterization of K562 cells on hemoglobin synthetic activity.

Two clones of the K562 human leukemic cell line were isolated according to hemoglobin (Hb) expression. One clone was expressed less than 5% (K562-L) and the other more than 90% (K562-H). The two clones did not exhibit any difference in cell growth or cell cycle. However, the Hb expression of K562-H cells was reduced by succinylacetone (S.A.). The above results suggested that the difference in the Hb production of K562-L and K562-H cells depended on the heme synthetic activity. On the other hand, glycophorin A was expressed to a greater extent on K562-L cells than on K562-H cells. These findings suggested that heme synthesis and the expression of glycophorin A on K562 cells were not always related. The CD11b and the CD61 were also expressed to a greater extent on K562-L cells than on K562-H cells, but the CD34 was not expressed on these cells.

Antigens, CD↗
PubMed1992

[Psychosomatic treatment of irritable bowel syndrome].

Irritable bowel syndrome (IBS) may be defined as a psychosomatic disease. Most primary care physicians do not want to undertake psychosomatic treatment, but may find it necessary in refractory patients. Brief psychosomatic treatments, providing patients with betterways to cope with stress, reduce the symptoms. The literature on the psychosomatic treatment for IBS is summarized. Supportive therapy and autogenic training that produce relaxation response appear to be effective. Other special psychological therapies that require specialized training, such as hypnosis, biofeedback, cognitive therapy, transactional analysis may be used for IBS but adequately controlled trials are lacking. It is certain that psychosomatic treatment take part in the management of IBS. Additional studies are needed to verify the effectiveness of these treatment for IBS.

Autogenic Training↗