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Biomedical subjects

S Seki

Publications and source records attributed to S Seki.

At least 307 records · Page 17Linked to original sources
PubMed1989

The value of the sinusoidal tcPO2 pattern in the evaluation and management of cyanotic congenital heart disease with ductus dependent lesions.

A characteristic sinusoidal tcPO2 pattern was observed in 17(27%) of 62 patients with congenital heart disease manifested by cyanosis or heart failure during the neonatal period. All of these 17 patients were definitively diagnosed by cardiac catheterization, as having 8 PPA; 3 ToF; 2 TGA + VSD + PA; 2 asplenia with PA; 1 TGA + VSD + PS; and 1 TA (no TGA type). The transcutaneous oxygen pressure pattern of these patients showed a sinusoidal change with a cycle length of 6-20 min with the maximum pressure not exceeding 50 torr and the minimum pressure occasionally close to 0 torr. This sinusoidal tcPO2 pattern was associated with various types of ductus-dependent congenital heart diseases and hence may be of diagnostic value. Transcutaneous oxygen pressure monitoring is also useful in evaluating the ductal response to PG. Other possible mechanisms underlying this phenomenon including biological oscillation should be considered.

Alprostadil↗
PubMed1989

Studies on bleomycin-induced repair DNA synthesis in permeable mouse ascites sarcoma cells.

To study the mechanism of DNA excision repair, a DNA repair system employing permeable mouse sarcoma (SR-C3H/He) cells was established and characterized. SR-C3H/He cells were permeabilized with a 0.0175% Triton X-100 solution. The permeable cells were treated with 1 mM ATP and 0.11 mM bleomycin, and then washed thoroughly to remove ATP and bleomycin. Repair DNA synthesis occurred in the bleomycin-damaged, permeable SR-C3H/He cells when incubated with ATP and four deoxyribonucleoside triphosphates. The repair nature of the DNA synthesis was confirmed by the BrdUMP density shift technique, and by the reduced sensitivity of the newly synthesized DNA to Escherichia coli exonuclease III. The DNA synthesis was optimally enhanced by addition of 0.08 M NaCl. Studies using selective inhibitors of DNA synthesis showed that aphidicolin-sensitive DNA polymerase (DNA polymerase alpha and/or delta) and DNA polymerase beta were involved in the repair process. The present DNA repair system is thought to be useful to study nuclear DNA damage by bleomycin, removal of the damaged ends by an exonuclease, repair DNA synthesis by DNA polymerases and repair patch ligation by DNA ligase(s).

Animals↗
PubMed1989

A cell-free system for studying a priming factor involved in repair of bleomycin-damaged DNA.

A simple cell-free system for studying a priming factor involved in the repair of bleomycin-damaged DNA was established. The template-primer used for the repair DNA synthesis was prepared by treating the closed circular, superhelical form of pUC19 plasmid DNA with 2.2 microM bleomycin and 20 microM ferrous ions. Single-strand breaks were introduced into pUC19 DNA by the bleomycin treatment, and the DNA was consequently converted largely into the open circular form. A system for repair of this bleomycin-damaged DNA was constructed with a priming factor, DNA polymerase (DNA polymerase beta or Klenow fragment of DNA polymerase I), ATP, T4 DNA ligase and four deoxynucleoside triphosphates. After incubation, the conformation of the DNA was analyzed by agarose gel electrophoresis and electron microscopy. The open circular DNA was largely converted to the closed circular DNA, indicating that the single-strand breaks of DNA were repaired. When the priming factor was omitted, DNA repair did not occur. The present system seemed to be applicable to the study of priming factors involved in the repair of DNA with single-strand breaks caused not only by bleomycin but also by ionizing radiation or active oxygen.

Bleomycin↗
PubMed1989

ADP effects on bleomycin-induced DNA repair synthesis and adenylate kinase activity in permeable mouse sarcoma cells.

DNA repair in bleomycin-pretreated, permeable mouse sarcoma (SR-C3H/He) cells requires ATP for at least two steps, the repair DNA synthesis step and the repair patch ligation step. ADP can apparently replace ATP in both steps. Maximal, 1.5-2 fold stimulation of repair DNA synthesis was observed with 5-10 mM ADP as well as 2.5-5 mM ATP. Repair patch ligation in the presence of 2.5 mM ADP occurred at almost the same high efficiency as it did in the presence of ATP. The ADP effect on DNA repair patch ligation was attributed to ATP formed from ADP by adenylate kinase in permeable cells, however the ADP effect on repair DNA synthesis could not be attributed solely to the formation of ATP in the same manner.

Adenosine Diphosphate↗
PubMed1989

Effects of ursodeoxycholic acid on intrahepatic cholestasis.

Ursodeoxycholic acid (UDCA) was administered to 16 intrahepatic cholestasis patients with severe jaundice, and its clinical effects were studied. As a result, it was remarkably effective in 6 patients, significantly effective in 5 patients, slightly effective in 2 patients and unchanged in 3 patients. As for the dose, when 600 mg/day was administered, it was effective in all patients, but even when only 150 mg/day was administered, it was effective in one patient (50%). Duration of treatment was 15 to 177 days with a mean of 55.3 days. These results suggested that while there is no adequate treatment for intrahepatic cholestasis with severe jaundice, UDCA should be considered as a possible method of treatment.

Adult↗
PubMed1989

Choleretic effects of ursodeoxycholic acid on experimentally-induced intrahepatic cholestasis.

When a lymphokine, the cholestatic factor, is intravenously injected into rats through a mesenteric vein, remarkable reductions in bile flow and bile acid excretion are observed. Using this experimentally-induced intrahepatic cholestasis model, the choleretic effects of ursodeoxycholic acid (UDCA) were studied. When UDCA was injected with the cholestatic factor, the reductions in bile flow and bile acid excretion were significantly suppressed. Remarkable choleretic effects were also noted, when UDCA was administered to normal rats. These results suggested that UDCA may be effective in the treatment of intrahepatic cholestasis.

Animals↗
PubMed1989

Serotonin and tryptamine metabolism in the acute hepatic failure model: changes in tryptophan and its metabolites in the liver, brain and kidney.

When heat-killed Propionibacterium acnes, a gram-positive anaerobe, is intravenously injected into mice followed by an intravenous injection of gram-negative lipopolysaccharide (LPS) 7 days later, most of the mice die of massive hepatic cell necrosis within 24 hours of LPS injection. Using this experimental model, acute hepatic failure was induced in mice, and the tryptophan metabolism in the liver, brain and kidney was studied. As a result, the tryptophan level was remarkably high in all three organs, and the metabolism of both the tryptamine pathway and serotonin pathway was induced. However, in the brain, the tryptamine metabolism was more induced compared to the serotonin, suggesting that the metabolites of tryptamine, may be involved in hepatic encephalopathy.

Acute Disease↗
PubMed1988

Release of peptide leukotrienes from rat Kupffer cells.

Kupffer cells isolated from the normal rat liver were incubated with calcium ionophore A23187, and the levels of peptide leukotrienes (LTC4, LTD4, and LTE4) contained in the culture supernatant were determined by the combined technique of reverse-phase high-performance liquid chromatography and radioimmunoassay. In response to A23187, Kupffer cells released LTC4, LTD4, and LTE4. After 10 min-preincubation of Kupffer cells with AA861, a 5-lipoxygenase inhibitor, the generation of LTC4, LTD4, and LTE4 from A23187-stimulated Kupffer cells was significantly suppressed. Platelet activating factor (PAF), a phospholipid mediator, significantly enhanced the release of LTC4, LTD4, and LTE4 from Kupffer cells stimulated with A23187. These results suggested that Kupffer cells may participate in inflammatory and immunologic events in the liver tissue by the release of peptide leukotrienes.

Animals↗
PubMed1988

Effects of an anti-tumor polysaccharide, schizophyllan, on interferon-gamma and interleukin 2 production by peripheral blood mononuclear cells.

We examined the effect of schizophyllan, a neutral glucan isolated from the culture filtrate of Schizophyllum commune Fries, on the production of interferon-gamma (IFN-gamma) and interleukin 2 (IL 2) from the mitogen-stimulated human peripheral blood mononuclear cells (PBMC). When the levels of IFN-gamma and IL 2 in the culture medium of phytohemagglutin (PHA)- or concanavalin A (Con A)-stimulated PBMC were measured by radioimmunoassay and enzyme-linked immunosorbent assay (ELISA) respectively, a significant increase in the production of both cytokines by schizophyllan was demonstrated. These results suggest that the increased production of IFN-gamma and IL 2 may be responsible for the anti-tumor activity of this glucan.

Concanavalin A↗
PubMed1988

Techniques for better suturing.

Suturing techniques enhancing the accuracy of suture placement and reducing the forces on the tissue being sutured were evaluated in six surgeons, each with 6 years' surgical experience. The accuracy was assessed by the distance between the actual and designated needle exit sites. Force was expressed in terms of the torque on the needle holder using a maximum of the torques (max. F), maximum derivative (dF/dt) and integral (IF). The effects of four factors (suturing techniques) on suturing were evaluated: (1) placement of the needle holder on the needle; (2) inclining the tissue at needle entrance, as is commonly done by elevating with forceps (unnoted role of the forceps); (3) adjustment of the needle's exit during suture placement, as is unknowingly employed in practice, and (4) variation between individual surgeons. All these factors affected the accuracy and force of suturing. Gripping the needle closer to the tip strongly reduced the max. F, dF/dt, and IF per time, as did inclining the tissue. Adjustment of exit improved accuracy, but has the potential for causing avoidable tissue injuries. Differences between surgeons suggest the necessity of addressing fundamental surgical techniques and formally incorporating them into the training programme.

Biomechanical Phenomena↗
PubMed1988

Effects of the polysaccharide chain of lipopolysaccharide in an experimental massive hepatic cell necrosis model in the mice.

When a small amount (1 microgram) of lipopolysaccharide (LPS) purified from Salmonella minnesota wild, Salmonella minnesota R60, and Salmonella minnesota R345 was intravenously injected into mice 7 days after heat-killed Propionibacterium acnes was intravenously injected, massive hepatic cell necrosis was induced and most of the mice died within 24 hours. However, when LPS from Salmonella minnesota R5 and Salmonella minnesota R7 and lipid A from Salmonella minnesota R595 were administered, the survival rate was much higher and no histological changes in the liver such as necrosis could be seen in any of the mice. In each of the LPS used in this study, the structure of the polysaccharide chain was different, and it decreased in the following order: Salmonella minnesota wild----Salmonella minnesota R60----Salmonella minnesota R345----Salmonella minnesota R5----Salmonella minnesota R7----Salmonella minnesota R595. This suggested that the polysaccharide chain of LPS played an important role in the induction of massive hepatic cell necrosis in this experimental model.

Animals↗
PubMed1988

Protective effects of a leukotriene inhibitor in an experimental massive hepatic cell necrosis model.

When heat-killed Propionibacterium acnes was intravenously injected into mice and seven days later, a small amount of gram-negative lipopolysaccharide was also intravenously injected, most of them died of massive hepatic cell necrosis. However, when azelastine hydrochloride, a leukotriene antagonist chemically known as 1(2H)-phthalazinone, 4-[(4-chlorophenyl)methyl]-2-(hexahydro-1-methyl-1H-azepine-4-yl)-, monohydrochloride, or AA861, 2-(12-hydroxydodeca-5, 10-diynyl)-3,5,6-trimethyl-1, 4-benzoquinone, a specific inhibitor of 5-lipoxygenase, was administered during this experimental induction of massive hepatic cell necrosis, the survival rate of the mice increased and the histological changes of the liver improved remarkably. These results suggested that leukotriene may be important for the induction of massive hepatic cell necrosis in our experimental model.

Animals↗
PubMed1988

Determination of serum cholestatic factor level by ELISA in drug-induced allergic hepatitis.

We have shown that intrahepatic cholestasis often observed in drug-induced allergic hepatitis may be induced by a kind of lymphokine, the cholestatic factor (CF). In this study, we measured the CF level in the serum of patients with jaundice by ELISA using anti-CF monoclonal antibody. As a result, CF was detected in the serum of most of the patients at the peak of jaundice, but it was not detected when the patients were recovering from jaundice. When the changes in the serum CF level were followed during the clinical course of a patient, it reached its maximum level before that of the serum total bilirubin level and quickly decreased thereafter. These results also suggest that intrahepatic cholestasis in drug-induced allergic hepatitis may be induced by CF.

Adult↗
PubMed1988

Effects of recombinant interleukin 2 on immunological effector cells of the peripheral blood in patients with HBe antigen-positive chronic hepatitis.

Changes in peripheral blood immunological effector cells after systemic administration of recombinant interleukin 2 (rIL2) were studied in 14 patients with HBe antigen-positive chronic hepatitis. The patients were intravenously injected with rIL2 for 4 weeks, and the experiments were performed using mononuclear cells isolated from the peripheral blood during and after rIL2 administration. No significant changes in OKT4-positive cell population, OKT8-positive cell population, OKT4/OKT8 ratio and Leu7-positive cell population were detected during and after intravenous injection of rIL2. However, the natural killer (NK) cell and lymphokine-activated killer (LAK) cell activities significantly increased in the fourth week of rIL2 administration, while the K cell activity in the antibody-dependent cell-mediated cytotoxicity reaction, antibody response, lectin-induced lymphocyte transformation and IL1 production of LPS-stimulated monocytes were not affected. These results suggest that IL2 increases the NK cell and LAK cell activities in vivo.

Adult↗
PubMed1988

Suturing techniques of surgeons utilizing two different needle-holder grips.

Sixteen surgeons familiar with grip 1 or grip 2 were randomly selected to test the accuracy of their suture method. The accuracy was tested in two ways: suture with and suture without wavering, while searching for an expected exit point after suturing started and by the distance deviated from a point in a 2 cm suture stride. With grip 1, the first and fourth fingers were put in the rings and the second finger was put around the leg of the holder, whereas with grip 2, all the fingers were put around the holder. Without waver, the mean value was 2 +/- 1.5 mm with grip 1 and 1.4 +/- 1.1 mm with grip 2 (p less than 0.01) and with waver, 1.2 +/- 1.1 mm and 1.1 +/- 10.9 mm (p value not significant). Wavering reduced the deviation (p less than 0.01 and p less than 0.05, respectively). In conclusion, the accuracy was not as precise as the surgeon expected and grip 2 was more accurate, although equivalent accuracy was gained by more wavering with grip 1, thus, there was a greater potential for injuring the tissue.

Humans↗