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Biomedical subjects

S Seki

Publications and source records attributed to S Seki.

At least 217 records · Page 12Linked to original sources
PubMed1994

[Factors determining the level of PaCO2 during laparoscopic cholecystectomy].

Factors responsible for the elevation of PaCO2 were investigated in 30 patients undergoing laparoscopic cholecystectomy using CO2 gas insufflation. Intraperitoneal insufflation of CO2 gas was performed to the level of 15 mmHg of intraperitoneal pressure in each patient and the following measurements were made: body height, body weight, body surface area (BSA), circumference of abdominal wall, obesity index, body mass index (BMI), operating time, total volume of insufflated CO2 gas, and change of peak inspiratory pressure. Rate of elevation of PaCO2 showed the highest correlation with BSA (correlation coefficient -0.691 [P < 0.01]) followed by body weight, body height, and circumference of abdominal wall. These results suggest that during laparoscopic cholecystectomy using CO2 gas insufflation, the degree of CO2 storage capacity has the highest effect on the elevation of PaCO2.

Adult↗
PubMed1994

Ultrastructural location of human hepatocyte growth factor in human liver.

Human hepatocyte growth factor has been purified from the plasma of patients with fulminant liver failure, but where this factor is produced in organs or cells of subjects with liver diseases is unknown. Therefore, we used a monoclonal antibody to human hepatocyte growth factor to stain cells in three normal and 29 diseased liver tissues by immunohistochemical techniques. By light microscopy, the immunostained cells seemed to be polymorphonuclear leukocytes because of their segmented nuclei. Some biliary epithelial cells also were stained. Electron microscopy confirmed that the immunostained cells with segmented nuclei were polymorphonuclear leukocytes and that the stained grains were on the membranes of rough endoplasmic reticulum, around specific or azurophilic granules and in the cell sap. Stained grains in the biliary epithelial cells were found sporadically on the inside and outside of the membranes of rough endoplasmic reticulum near the nuclei. Human hepatocyte growth factor is now known to be the same protein as scatter factor and tumor cytotoxic factor, both of which are produced by human fibroblasts in culture, but our results suggest that polymorphonuclear leukocytes in diseased livers are one cellular source of circulating human hepatocyte growth factor. The immunostaining properties of biliary epithelial cells in diseased livers also suggest that the cells produce and secrete human hepatocyte growth factor.

Adult↗
PubMed1993

Molecular cloning of partial cDNAs for rat DNA topoisomerase II isoforms and their differential expression in brain development.

cDNA segments for DNA topoisomerase II were amplified from rat brain RNA after reverse transcription by the polymerase chain reaction, using degenerate oligonucleotide primers deduced from the conserved regions of topoisomerase II of higher eukaryotes. The cDNA product from a successful amplification was homogeneous in length but heterogeneous in sequence. Restriction mapping of the cloned cDNA fragments revealed that they consisted of two distinct sequence groups. DNA sequencing of representative clones from each group, designated A and B, showed that they are highly homologous to cDNAs of human topoisomerase II isoforms, alpha and beta, respectively. Northern blot analysis indicated that the transcript level for rat topoisomerase II alpha was high in embryonic brain and in the cerebellum of 2-day newborns, followed by rapid decrease to a undetectable level at 4 weeks after birth. In contrast, rat topoisomerase II beta transcript was present throughout the embryonic and postnatal stages. In the developing cerebellum, cells expressing topoisomerase II alpha were confirmed exclusively to the outer mitotic zone of the external granular layer, whereas the transcript of topoisomerase II beta was detected over the entire cortical region. These results clearly indicate that the isoform alpha is expressed only in proliferating cells. The differential expression of topoisomerase II isozymes was also observed among developed tissues. Therefore, the isozymes are most likely to be involved in the following different physiological processes: topoisomerase II alpha in cell proliferation, and topoisomerase II beta in some processes unrelated to cell proliferation.

Amino Acid Sequence↗
PubMed1993

Activity gel and activity blotting methods for detecting DNA-modifying (repair) enzymes.

Zymographical methods (activity gel, overlay gel, activity blot and activity blotting) for detecting DNA-modifying (repair) enzymes are reviewed. Emphasis is put on the novel activity blotting method in which DNA repair enzymes electrophoresed on a gel are blotted and detected on a damaged DNA-fixed nylon membrane. Its practical procedures, including a non-radioactive detection procedure, and representative results are also described.

Animals↗
PubMed1993

Identification and characterization of a nuclear scaffold protein that binds the matrix attachment region DNA.

The association of nuclear DNA with the nuclear matrix (scaffold) is mediated by defined segments of DNA called matrix association region (MAR). By using a plasmid harboring a portion of the Ig kappa gene within which MAR had been located, we searched for proteins recognizing MAR in the nuclear scaffold components electrophoretically separated and blotted onto a membrane. In the presence of nonspecific competitor DNA, the labeled plasmid selectively bound to a protein with apparent molecular weight of 120,000 (designated SP120). The protein was purified directly from SDS-polyacrylamide gels and renatured by a guanidine hydrochloride procedure. The DNA region in the plasmid responsible for the binding to the solubilized SP120 coincided with the 365-base pair HindIII-HinfI fragment that had been identified as MAR. In solution, SP120 exhibited a cooperative mode of interaction with the end-labeled MAR fragment. Measurement of relative affinities of MAR subfragments to SP120 showed that the whole region is required for efficient binding. This is consistent with the minimal length for MAR estimated thus far by in situ mapping experiments. The MAR derived from another gene, fushitarazu, also bound specifically to SP120. Immunostaining of whole cells and isolated nuclei with a monoclonal antibody raised against SP120 indicated that the protein is localized in a nuclear skeletal structure. These results suggest the involvement of SP120 in the MAR-mediated anchorage of nuclear DNA to the nuclear scaffold.

Animals↗
PubMed1993

Na+/H+ exchanger and reperfusion-induced ventricular arrhythmias in isolated perfused heart: possible role of amiloride.

The roles of the Na+/H+ exchange system in the development and cessation of reperfusion induced ventricular arrhythmias were studied in the isolated perfused rat heart. The hearts were perfused in the working heart mode with modified Krebs Henseleit bicarbonate (KHB) buffer and whole heart ischemia was induced by a one-way ball valve with 330 beat/min pacing. Ischemia was continued for 15 min followed by 20 min of aerobic reperfusion (control). Amiloride (1.0 mM), an inhibitor of the Na+/H+ exchange system, was added to the KHB buffer only during reperfusion (group B) or only during ischemic periods (group C). Electrocardiographic and hemodynamic parameters were monitored throughout the perfusion. Coronary effluent was collected through pulmonary artery cannulation and PO2, PCO2, HCO3- and pH were measured by blood-gas analyzer. The incidence of reperfusion induced ventricular arrhythmias was 100%, 100% and 0% in control, group B and group C, respectively. The mean onset time of termination of reperfusion arrhythmias was significantly shorter in group B than in control. PCO2 increased from 39.0 +/- 0.9 to 89.3 +/- 6.0 mmHg at the end of ischemia in control and from 40.6 +/- 0.4 to 60.5 +/- 5.8 in group C, the difference between groups was statistically significant. HCO3- level decreased from 21.8 +/- 0.1 to 18.3 +/- 0.5 mmol/l in control, however, this decrease was significantly inhibited in group C (from 22.0 +/- 0.5 to 20.3 +/- 0.2). The increase in PCO2 and the decrease in HCO3- in group B were similar over time to those observed in control.(ABSTRACT TRUNCATED AT 250 WORDS)

Amiloride↗
PubMed1993

The surgeon's technical skill in suturing: an analysis of the actual suture tracks.

Ideal suturing was defined as advancing a needle along its curvature (needle circle) to minimize tissue trauma, while placing the suture with its intended span and tissue bite in the expected place. Actual suture tracks were analyzed to find the keys to produce such suturing. Correspondence of those tracks to the ideal track was then determined by the span, the initial needle angle (IA) into the tissue, and the center of the needle circle. Eight surgeons with 4-7 years of experience produced 22 ideal sutures in two types of tissue simulants: The entrance and exit points of the needle were level in flat suturing, while the entrance point was slanted 45 degrees for slant saturing. The correspondence was better with slant suturing than flat suturing (P < 0.01). The IA in flat suturing was 49.0 +/- 2.0 (mean +/- SE) degrees versus 33.0 for ideal suturing (P < 0.01), while that in slant suturing was 35.5 +/- 1.9 (P: ns). In conclusion, the IA was the key to good results, and was optimized in slant suturing, which was instinctively utilized in practice by using forceps. The forceps avoided a derangement of suturing stemming from the configuration of the needle employed and from the range of motion of the surgeon's arm (human engineering), while satisfying the surgeons inclination to take a large IA.

Clinical Competence↗
PubMed1993

Pulmonary oxygen transfer deficits of diabetic origin in patients undergoing coronary artery bypass grafting.

The objective of this study was to determine the effects of a diabetic disposition on pulmonary gas exchange by examining 72 patients who underwent coronary artery bypass grafting (CABG), using the arterial/alveolar oxygen tension ratio [(a/A)PO2] as a criterion. Patients were divided into a diabetic (DM) group and a nondiabetic (non-DM) group. The postoperative blood gases and hemodynamic data measured when the blood glucose level was at a maximum on the day of CABG were used as the postoperative pulmonary gas exchange indices, and the physicians who managed these patients were unaware of this study. The preoperative (a/A)PO2 ratio was 0.66 +/- 0.03 (SE) in the DM group and 0.78 +/- 0.02 in the non-DM group (P < 0.01), while the postoperative ratios were 0.42 +/- 0.03 and 0.52 +/- 0.03, respectively (P = 0.01). The correlation coefficient (r) for regression analysis of the relation between the postoperative PaO2/FIO2 ratio and the postoperative (a/A)PO2 ratio was 0.99 in the DM group (P < 0.01) and 0.88 in the non-DM group (P < 0.01). The r values of the relation between (a/A)PO2 and (A-a)PO2 were -0.68 (P < 0.00) and -0.84 (P < 0.01), while those for the respiratory index were -0.87 (P < 0.01), and -0.93 (P < 0.01), respectively. Thus, pulmonary oxygen transfer was compromised before and after CABG in the DM group compared to the non-DM group. Moreover, the PaO2/FIO2, being the simplest pulmonary gas exchange index to calculate, was a reliable substitute for the (a/A)PO2 ratio during the early postoperative management of CABG patients.

Coronary Artery Bypass↗
PubMed1993

In vivo antimelanoma effects of 4-S-cysteaminylphenol, a newly synthesized therapeutic agent specific to melanoma.

Antimelanoma effects of 4-S-cysteaminylphenol (4-S-CAP), which is a newly synthesized melanin precursor, as a chemotherapeutic agent specific to malignant melanoma were determined in an in vivo system using mouse B16 melanoma. The intraperitoneal injection of 4-S-CAP induced a slight delay in the growth period of subcutaneous melanoma of C57BL/6 mice. Survival times of mice after treatment with 4-S-CAP were a little longer than those of control mice (P < 0.05), although all mice died from the local growth of tumours. The viable cell ratio of in vivo subcutaneous tumour cells reduced to 52.8% within 24 h after treatment with 4-S-CAP, but the ratio had recovered to the control level 72 h after treatment (> 90%). Similarly, the proliferating-cell-nuclear-antigen-positive cell ratio of melanotic melanoma had reduced 24 h after treatment and recovered within 72 h after treatment, while 4-S-CAP had no effect on amelanotic tumours. The formation of lung colonies by intravenous inoculation of malignant melanoma cells was compared between mice with intraperitoneal injection of 4-S-CAP and phosphate-buffered saline only. The 4-S-CAP-treated mice had significantly fewer lung colonies compared with the control mice (P < 0.01). The results indicate that the agent, 4-S-CAP, would have a therapeutic effect on malignant melanoma for a short time in vivo and therefore the agent can be effective against a small number of tumour cells, such as lung colonies, although it had little effect on the local tumours.

Animals↗
PubMed1993

Analysis of proliferating biliary epithelial cells in human liver disease using a monoclonal antibody against DNA polymerase alpha.

The proliferative activity and ultrastructural characteristics of proliferating biliary epithelial cells were analysed immunohistocytochemically in 39 biopsied liver specimens from patients with acute viral hepatitis, chronic hepatitis and liver cirrhosis using a monoclonal antibody against DNA polymerase alpha (DNA-PA). In acute viral hepatitis with perivenular confluent necrosis, proliferation of typical bile ducts was found frequently in portal areas. In chronic aggressive hepatitis and cirrhosis, ductular proliferation of both typical and atypical forms was found in enlarged portal and periportal areas and in confluent necrotic areas. The number of proliferating biliary epithelial cells that stained positive for DNA-PA was small. There were very few positively stained cells in atypical bile ducts in confluent necrotic areas of cirrhosis. Atypical bile ducts seen in chronic aggressive hepatitis, cirrhosis and acute hepatitis with confluent necrosis were positively stained for both cytokeratins 8 and 19. In cirrhosis, the number of stained biliary epithelial cells in typical bile ducts was larger than the number of such cells in atypical bile ducts (P < 0.01). By electron microscopy, the cells positively stained for DNA-PA were mostly so-called clear cells with irregular nuclei containing coarse nucleoplasm, and a few small cells with scanty cytoplasm and few organelles.

Adult↗
PubMed1993

Long-term therapeutic efficacy of interferon for patients with chronic hepatitis C.

Interferon is being used for therapy of chronic hepatitis C, but its long-term results have not been reported. We studied 65 patients with this disease who were monitored for at least 2 years after completion of the therapy. Almost all patients who had responded to therapy at 6 months after the end of therapy had normal levels of alanine aminotransferase (ALT) when evaluated later. The level of ALT became normal for the first time in some patients more than 6 months after therapy ended. The level of ALT in many of the patients without HCV RNA had become normal 6 months after the end of the therapy. One of three schedules was employed: three times weekly long-term; daily for two weeks and none for two weeks in a cycle; and daily for several weeks; 57%, 29%, and 17% of the patients on these schedules came to have normal ALT levels. Patients without HCV RNA at six months after completion of therapy tended to have higher responses in terms an increased level of 2',5'-oligoadenylate synthetase of mononuclear cells in vitro before therapy began. However, therapy three times per week was effective even for some patients judged not responsive to IFN by this test. The results showed that IFN therapy was effective for chronic hepatitis C when judged by long-term results.

Adult↗
PubMed1993

A possible cause of heterogeneity of mammalian apurinic/apyrimidinic endonuclease.

1. Mammalian major apurinic/apyrimidinic (AP) endonuclease, APEX nuclease (M(r) 35.4 kDa) was purified from HeLa cells. A hybrid protein (M(r) 36.4 kDa), which was expressed in BW2001 strain cells of E. coli, comprising human APEX nuclease headed by 10 additional amino acids was also purified. 2. The purified preparations were frequently associated with 31-, 33- and 35-kDa peptides having AP endonuclease activity. 3. The 33- and 35-kDa peptides were suggested to be formed from the hybrid protein or APEX nuclease during their purification processes by proteolytic cleavage with subtilisin-like protease. The 31-kDa peptide was thought to be produced by chemical cleavage of the aspartyl-prolyl bond of APEX nuclease. 4. The results support the notion that some of AP endonuclease heterogeneity based on the molecular weight difference are caused by proteolytic (and chemical) cleavage of a species of AP endonucleases during the extraction and purification.

Amino Acids↗
PubMed1993

Expression of a putative catalytic domain of the human APEX nuclease (a major apurinic/apyrimidinic endonuclease) in Escherichia coli.

1. Sequence analyses of APEX nuclease, a mammalian major apurinic/apyrimidinic (AP) endonuclease homologous to Escherichia coli exonuclease III, suggested that APEX nuclease is organized into two domains, a Mr 6000 N-terminal domain containing nuclear location signals and a Mr 29,000 C-terminal catalytic domain. 2. In order to study the enzyme structure further, vectors expressing APEX nuclease (pTAPXH1) and the Mr 29,000 C-terminal region (pTAPXH61) were constructed using cDNA (APX cDNA) for the human APEX nuclease and pTrc99A plasmid. The constructs were introduced into BW2001 strain (xth-11, nfo-2) cells of E. coli to produce transformants designated as BW2001/pTAPXH1 and BW2001/pTAPXH61, respectively. Both the APEX nuclease expressed in BW2001/pTAPXH1 and the Mr 29,000 C-terminal peptide expressed in BW2001/pTAPXH61 were partially purified by column chromatography and highly purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. 3. The purified APEX nuclease and the Mr 29,000 C-terminal peptide both showed equally high AP endonuclease activity which indicates that the Mr 29,000 C-terminal region of the APEX nuclease is (or contains) the AP endonuclease domain.

Amino Acid Sequence↗
PubMed1993

Age-associated increase of CD5+ B cells in the liver of autoimmune (NZB x NZW) F1 mice.

The liver has been demonstrated to be a major site for extrathymic differentiation of T cells. In this study, an identification of CD5+ B cells, which are responsible for the onset of autoimmune disease by virtue of autoantibody production, was performed in autoimmune (NZB x NZW) F1 mice. An age-associated increase of CD5+ B cells was demonstrated in the liver of these mice. Although CD5+ B cells (i.e., CD5+IgM+ and CD5+B220+) constituted a minor population of hepatic mononuclear cells (MNC) (< 5%) when mice were young (8 weeks), a large population of CD5+ B cells (10 to 30% of whole MNC) was identified in the liver of mice aged 25 to 30 weeks after the onset of disease. Such age-dependent increase of CD5+ B cells was not observed in any other strains including NZB, NZW, C3H/He and BALB/c mice. The phenotype of hepatic CD5+ B cells was the same as that of CD5+ B cells in the peritoneal cavity and spleen, showing dull-CD5, bright-IgM and dull-B220. High levels of CD5+ B cells were observed in the peritoneal cavity and liver, but not in the spleen nor in any other lymphoid organs in mice aged 30 weeks. Radioimmunoassay of autoantibodies in the 5-day culture supernatants demonstrated that hepatic MNC were unable to produce any amounts of IgM- and IgG-autoantibodies against double-stranded DNA and single-stranded DNA, despite the increased proportion of CD5+ B cells. On the other hand, peritoneal exudate cells produced only IgM-, but not IgG-, autoantibodies, whereas splenic cells were able to produce both IgM- and IgG-autoantibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1993

Inhibition of cisplatin-mediated DNA damage in vitro by ribonucleotides.

Effects of ribonucleotides on cis-diamminedichloroplatinum(II) (cisplatin)-mediated DNA damage were studied by incubating pUC18 DNA with cisplatin in the presence of nucleotide, and by monitoring conformational change and sensitivity change to restriction enzyme HpaII of the DNA due to the platinum-DNA adduct formation. The cisplatin-mediated DNA damage was inhibited in a dose-dependent fashion by ATP or GTP, substantially at their physiological intracellular concentrations, and almost completely by 5 mM ATP or 2 mM GTP. The inhibitory effect of nucleotide on the platination of DNA was in the order of GTP > ATP >> CTP > UTP, and of nucleoside triphosphate > nucleoside diphosphate > nucleoside monophosphate. Nucleoside did not show any significant effect on platination of DNA. To elucidate the mechanism of the nucleotide effects on platination of DNA, interaction between ATP or GTP and cisplatin was analyzed by high-performance liquid chromatography. The results suggested that ATP inhibits cisplatin-mediated DNA damage both by forming a platinum-ATP adduct and by non-covalent ionic interaction with cisplatin, while GTP acts largely by forming platinum-GTP adducts.

Cisplatin↗
PubMed1993

Epidermodysplasia verruciformis accompanied by familial large granular lymphocytosis and a decrease in T lymphocytes.

A 40-year-old man with epidermodysplasia verruciformis showed a decrease in peripheral blood T cells and abnormal expansion of large granular lymphocytes, accompanied by increased natural killer cell activity. Surface marker analysis of his large granular lymphocytes demonstrated that the subset, CD 57+ and CD 16+, had increased. His father, who had no skin lesions of epidermodysplasia verruciformis, displayed similar blood changes and his brother showed a decrease in T cells and a slight increase in CD 16+ natural killer cells, whereas his mother revealed only a slight decrease in T cells. Our present study indicates that epidermodysplasia verruciformis might be associated with hereditary abnormal expansion of large granular lymphocytes and a decrease in T cells.

Adult↗