Biomedical subjects

S Seki

Publications and source records attributed to S Seki.

At least 145 records · Page 8Linked to original sources

PubMed1998

[Reduction of pain on injection of propofol: a comparison of fentanyl with lidocaine].

We compared the effect of fentanyl and lidocaine on pain during injection of propofol. One hundred and sixty patients premedicated with midazolam were randomly allocated to one of four groups (n = 40, respectively); Group C, propofol 2 mg.kg-1; Group F, fentanyl 0.1 mg 3 min prior to propofol; Group L, lidocaine 40 mg added to 200 mg propofol; Group FL, fentanyl 0.1 mg 3 min prior to propofol mixed with lidocaine 40 mg. Propofol was injected via a vein on the dorsum of the hand in a half of the patients in each Group or the forearm vain in the other half. The incidence of pain was significantly less in both Group F (40%) and Group L (35%) compared with Group C (80%, P < 0.01). There was no significant difference in the incidence of pain between Group F and Group L. Group FL had the least incidence of pain (5%) of all Groups. Injection via the forearm vain tended to reduce the severity of pain compared with the vain on the dorsum of the hand. The time until loss of consciousness was significantly less in the groups receiving fentanyl than the groups without fentanyl (P < 0.01). In conclusion, prior administration of fentanyl is as effective as premixing of lidocaine in preventing the pain on injection of propofol, and the simultaneous application of them may abolish the pain.

Adult↗

PubMed1998

Regulation of stellate cell proliferation by lipopolysaccharide: role of endogenous nitric oxide.

We studied the effect of lipopolysaccharide (LPS) on the proliferation of culture-stimulated rat stellate cells. DNA synthesis as determined by [3H]-thymidine incorporation was significantly suppressed by up to 52% compared with the control culture in the presence of LPS (> 5 ng/mL). Such an inhibitory effect of LPS was dramatically augmented in the presence of interferon-gamma (IFNgamma). Lipopolysaccharide alone or in combination with IFNgamma activated transcription factors AP-1 and NF-kappaB, and elicited nitric oxide (NO) production by stellate cells by inducing NO synthase. Inhibition of NO production by the addition of L-arginine antagonists to the culture, partially cancelled such an inhibitory effect of LPS and/or IFNgamma on DNA synthesis without affecting the activation of AP-1 and NF-kappaB and the NO synthase level. The cellular level of cyclic guanosine monophosphate (cGMP) increased in response to LPS and IFNgamma, and dibutyryl cGMP or 8-bromo-cGMP inhibited the incorporation of [3H]-thymidine in a dose-dependent manner. These results indicate that LPS is potent in modulating stellate cell proliferation by some NO- and cGMP-dependent mechanism.

Animals↗

PubMed1997

Requirement of IL-4 and liver NK1+ T cells for concanavalin A-induced hepatic injury in mice.

Con A-induced hepatic injury of mice accompanied by elevated transaminase was inhibited after in vivo depletion of liver NK cells and NK1+ T cells with intermediate TCR by anti-NK1 Ab or anti-IL-2Rbeta Ab. However, depletion of liver NK cells alone by anti-asialo-GM1 Ab did not inhibit hepatic injury. Although depletion of NK1+ T cells inhibited Con A-induced IL-2R expression of CD4+ high TCR (TCRhigh) cells and IL-4 mRNA expression of hepatic mononuclear cells, exogenous IL-4 engendered Con A-induced hepatic injury and endowed the expression of IL-2R of CD4+ TCRhigh cells. It was also found that in vivo treatment with anti-IL-4 Ab before Con A administration inhibited Con A-induced hepatic injury. In addition, although Con A did not induce hepatic injury in MHC class I-deficient mice, exogenous IL-4 again engendered severe hepatic injury in these mice. Further, while serum TNF-alpha levels induced by Con A were greatly decreased in NK1+ T cell-depleted mice and class I-deficient mice, TNF-alpha levels were recovered by exogenous IL-4. These findings reveal that although CD4+ TCRhigh cells in the liver and their production of TNF-alpha are the direct effectors of Con A-induced hepatic injury, liver NK1+ T cells also play an important role in this hepatitis model. Con A hepatitis may serve as an experimental model for human autoimmune hepatitis.

Adjuvants, Immunologic↗

PubMed1997

cDNA cloning of a novel amphiphysin isoform and tissue-specific expression of its multiple splice variants.

Amphiphysin, an SH3-domain containing protein concentrated in nerve terminals, is believed to be involved in the synaptic vesicle recycling. We have cloned cDNAs of a novel isoform of amphiphysin (amphiphysin II) by exploiting sequence information for homologous ESTs deposited in databases. At least 9 different subtypes of the isoform with 50-60% amino acid identity to the human amphiphysin were identified by a conventional library screening and PCR amplification of cDNA libraries. Each subtype probably represents a splice variant of a single gene transcript. Analysis of mRNA expression in various tissues by RT-PCR showed that the isoform is ubiquitously distributed. The expression spectrum of the isoform subtypes, however, is significantly different in several tissues examined, suggesting that they are involved in the regulation of endocytic processes that are unique to each cell type.

Amino Acid Sequence↗

PubMed1997

Regulation by cAMP of STAT1 activation in hepatic stellate cells.

Previously we reported that dibutyryl cAMP and phosphodiesterase inhibitor methylxanthines block rat stellate cell proliferation. To analyze the underlying mechanism, modulation by these agents of platelet-derived growth factor (PDGF)/BB-stimulating signal pathway was studied. Without reducing STAT1 protein level, these agents were found to attenuate STAT1 activation in stellate cells stimulated with PDGF/BB as revealed by an electrophoretic mobility shift assay. Inhibitory effect started 12 h after exposure of the cells to these agents at concentrations of more than 100 microM. These agents had no effects on DNA binding activity of STAT1 that had already been activated. Treatment with these agents failed to affect the function of PDGF receptors except for partial attenuation of phospholipase C activation under PDGF/BB stimulation. The present results indicate that inhibition of STAT1 activation may be one of factors involved in the cAMP-dependent stellate cell growth arrest.

1-Methyl-3-isobutylxanthine↗

PubMed1997

Effects of functional endoscopic sinus surgery on maxillary sinus mucosa.

OBJECTIVE: To compare the preoperative and postoperative changes on ciliary surface of maxillary sinus mucosa in patients treated with functional endoscopic sinus surgery. DESIGN: The maxillary mucosa of both the superolateral wall and the ostium were sampled during the operation and 6 to 12 months (mean duration, 7.6 months) after the operation. Ciliary surface was determined using scanning electron microscopy in combination with an image analyzer and was expressed in terms of ciliary area, which is the percentage of mucosal surface occupied by cilia. SETTING: The samples were taken at a hospital-based clinic. An electron microscopic study was performed at Mie University School of Medicine, Mie, Japan. PATIENTS: Sixteen patients (20 maxillary sinuses) undergoing functional endoscopic sinus surgery for treatment of chronic sinusitis. RESULTS: The mean (+/-SD) ciliary area before the surgery was 60.7%+/-28.8% and 39.9%+/-21.5% in the superolateral wall of the maxillary sinus and the ostium of the maxillary sinus, respectively. The ciliary area of the superolateral wall was significantly higher than that of the ostium (P<.001). The mean (+/-SD) postoperative ciliary area value was 74.3%+/-22.6% in the superolateral wall and 51.3%+/-16.1% in the ostium. These postoperative values were significantly higher than the preoperative values (P<.001). CONCLUSIONS: This study showed that the maxillary sinus mucosa in chronic sinusitis is capable of regeneration, and the damaged ciliated epithelium could return toward normal with the improvement of ventilation and drainage of the maxillary sinus following functional endoscopic sinus surgery.

Adolescent↗

PubMed1997

Mouse liver T cells: their change with aging and in comparison with peripheral T cells.

Mouse liver contains both IL-2Rbeta- (or low positive) high T-cell receptor (TCR(hi)) cells and IL-2Rbeta+ intermediate TCR (TCR(int)) cells. TCR(int) cells consist of natural killer 1.1 (NK1)+ and NK1- subsets. NK1- TCR(int) cells increase constantly with age whereas TCR(hi) cells decrease. NK1+ TCR(int) cell proportions in the liver increase until middle age and decrease thereafter. Although NK1+ TCR(int) cells in other organs are few regardless of age, NK1- TCR(int) cells gradually appear in other lymphoid organs with aging. Skewed usage of Vbeta7 and Vbeta8 TCR was observed in NK1+ TCR(int) cells in the liver but the predominance was less obvious in NK1- TCR(int) and TCR(hi) cells in the liver and other organs. TCR V alpha14 messenger RNA (mRNA) was detected in NK1+ TCR(int) cells but not in the other two populations. In contrast, although NK1+ TCR(int) cells contain virtually no V alpha11+ T cells, NK1- TCR(int) cells contain a much higher proportion (approximately 12%) of V alpha11+ T cells, whereas approximately 4% of TCR(hi) cells are V alpha11+. NK activities of liver mononuclear cells (MNC) and splenocytes decrease with aging, although the former is always greater than the latter. NK activity of liver MNC is a function of NK cells, partly NK1+ TCR(int) cells but not NK1- TCR(int) cells or TCR(hi) cells. These results suggest that lymphocytes of liver and other organs at old age are no longer occupied solely by conventional thymus-derived T cells, and the increase of extrathymic IL-2Rbeta+ NK1- TCR(int) cells in liver and periphery could be closely related to immunological changes with aging.

Aging↗

PubMed1997

Characterization of cytokine and iNOS mRNA expression in situ during the course of experimental autoimmune myocarditis in rats.

Ribonuclease protection assay was used to demonstrate mRNA expression of several cytokines as well as inducible NO synthase (iNOS), constitutive endothelial NO synthase (cNOS) and perforin in the myocardium during the course of experimental autoimmune myocarditis (EAM) in rats. Interleukin 2 (IL-2) appeared in the initial inflammatory phase (day 14), subsided in the maximum inflammatory phase (day 19) and disappeared by the recovery phase (day 25). mRNA of IL-3 beta, interferon gamma INF-gamma and tumor necrosis factor alpha (TNF-alpha) were detected only in the maximum inflammatory phase and iNOS also appeared for several days at this time. In contrast. IL-10 mRNA was detected after the maximum inflammatory stage and persisted into the recovery phase (days 25-36). Although transforming growth factor beta 1 (TGF-beta 1) could be detected in all phases, the expression was markedly enhanced in the maximum inflammatory phase and gradually diminished (around day 36) to basal levels. Perforin mRNA was not detected at any point in the disease. Besides macrophages and CD4 T cells, a number of neutrophils were found in the myocardium especially at peak inflammatory stage. We suggest that antigen (Ag) primed Ag presenting cells or macrophages interact with T cells (Th1) to produce IL-2 and subsequent IFN-gamma, which further activates macrophages in the myocardium. Consequently, TNF-alpha and iNOS may inflict tissue damage to myocardium. It is also suggested that TGF-beta) and one representative Th2 cytokine, IL-10, help inhibit inflammation. These findings suggest that Th1 and Th2 cytokines are produced at different stages of EAM and modulate the inflammation and the course of EAM.

Animals↗

PubMed1997

Induction of apoptosis in a human hepatocellular carcinoma cell line by a neutralizing antibody to transforming growth factor-alpha.

A cell line derived from a Japanese man with hepatocellular carcinoma was established in culture and designated OCUH-16. The cell line has the morphological and chromosomal features of hepatocellular carcinoma cells and has a short doubling time (approximately 33 h). OCUH-16 cells were shown to express transforming growth factor-alpha (TGF-alpha) in addition to albumin, DNA polymerase-alpha, c-JUN, and the retinoblastoma gene product. Electron microscopy revealed TGF-alpha immunoreactivity associated with the cell membrane, but TGF-alpha was not detected in medium conditioned by OCUH-16 cells by enzyme-linked immunosorbent assay. Reverse transcription and polymerase chain reaction analysis revealed the presence of TGF-alpha messenger RNA in these cells. Culture of OCUH-16 cells in the presence of a neutralizing antibody to TGF-alpha inhibited cell proliferation and induced many cells to undergo apoptosis (programmed cell death). These observations suggest that endogenous TGF-alpha is necessary for OCUH-16 cell growth.

Antibodies, Monoclonal↗

PubMed1997

Accumulation of wild-type p53 in astrocytomas is associated with increased p21 expression.

Approximately one quarter of human astrocytomas show immunohistochemical positivity for p53 protein but lack p53 gene mutations, which could reflect either an accumulation of wild-type p53 protein or an inadequate sensitivity of mutation detection. Since wild-type p53 up-regulates p21 expression, increased p21 expression in those astrocytomas with p53 accumulation in the absence of mutations would argue that the protein was wild type in these tumors. We therefore compared p21 expression with p53 gene and protein status in 48 primary human astrocytomas. Single-strand conformation polymorphism analysis and direct sequencing of the p53 gene showed mutations in 11 tumors (22.9%), while immunohistochemistry revealed positive staining in 19 cases (39.6%). Those tumors with p53 immunopositivity in the absence of p53 mutation had significantly increased p21 expression when compared to either mutant p53 or p53-immunonegative cases. Neither p53 nor p21 status correlated with proliferation indices, as assessed by Ki-67 immunohistochemistry. These results support the hypotheses that functionally wild-type p53 accumulates in some astrocytomas, and that alternative cell cycle checkpoints (such as the p16 pathway) may be more important than p21 in regulating proliferation in astrocytomas.

Adolescent↗

PubMed1997

Expression of cytochrome P450 isoforms in rat hepatic stellate cells.

The current study evaluated the expression and the inducibility of cytochrome P450 isoforms in rat hepatic stellate cells (HSCs). Immunoblotting study revealed that HSCs expressed several P450s and CYP2C11, 3A2, and 2D1 were major isoforms. The levels of CYP2B1, 2C11, 2D1, 2E1, and 3A2 in HSCs were 14 - 38% of those in hepatocytes. CYP1A2 content was similar in each cell type. These P450 levels in HSCs gradually decreased during culture as seen in hepatocytes; the level of CYP3A2 rapidly, whereas that of CYP2D1 slowly decreased. Phenobarbital, a typical inducer of CYP3A2 and 2B1 increased CYP3A2 level as well, but had less potency in the induction of CYP2B1 in HSCs. These results indicate that multiple P450 isoforms were present in HSCs, but their content and inducibility were different between HSCs and hepatocytes.

Animals↗

PubMed1997

Autologous killing by a population of intermediate T-cell receptor cells and its NK1.1+ and NK1.1- subsets, using Fas ligand/Fas molecules.

Self-reactive clones, estimated by anti-V beta monoclonal antibodies (mAb) in conjunction with the Mls system, are confined to a population of intermediate (int) T-cell receptor (TCR) (or CD3) cells (i.e. TCRint cells), but are not found among TCRhigh cells. The next questions to be answered are whether autologous killing is confined to TCRint cells and how such killing is mediated. In this study, 51Cr-labelled thymocytes of syngeneic or allogeneic origin were used as target cells (4-hr assay). When liver and splenic mononuclear cells (MNC) obtained from B6 mice were used as effector cells, prominent autologous killing was seen in liver MNC, but not splenic MNC. Such killing was not seen when thymocytes from B6-lpr/lpr mice (i.e. Fas-) were used as target cells, nor when liver MNC from MRL-gld/gld mice (i.e. Fas ligand-) were used as effector cells (target thymocytes of MRL(-)+/+ mice). Cell separation experiments using a cell sorter revealed that autologous killing was mediated for the most part by CD3int cells, while allogeneic killing was mediated entirely by natural killer (NK) cells, TCRint cells and TCRhigh cells. Among CD3int cells, the NK1.1+ subset (i.e. NK1.1+ T cells) manifested a higher level of autologous killing than did the NK1.1- subset. Consistent with the results of a functional assay, it was found by reverse-transcription-polymerase chain reaction (RT-PCR) assay that CD3int cells among liver MNC showed the expression of Fas ligand mRNA, while thymocytes expressed Fas mRNA. When class I major histocompatibility complex (MHC)- thymocytes (from beta 2-microglobulin-deficient mice) were used as target cells, NK cells, but not CD3int cells, showed potent cytotoxicity. These results suggest that autologous killing is a major function of TCRint cells with self-reactivity, and that such killing is mediated by means of Fas ligand/Fas molecules.

Animals↗

PubMed1997

Antimetastatic effect of NK1+ T cells on experimental haematogenous tumour metastases in the liver and lungs of mice.

Depletion of both natural killer 1.1+ (NK1+) intermediate alpha beta T-cell receptor (int T) cells and NK cells by in vivo treatment with anti-NK1 antibody greatly increased hepatic metastases of intravenously injected EL4 cells as well as pulmonary metastases of 3LL cells in C57BL/6 mice. However, depletion of NK cells alone by anti-asialo GM1 (AGM1) antibody treatment did not increase the metastases in either organ. Interleukin-12 (IL-12) administration into mice induced strong cytotoxicities of NK cell-depleted liver and lung mononuclear cells (MNC) comparable to those without NK-cell depletion and inhibited metastases in either organ. In contrast, in both NK cell- and NK1+ int T-cell-depleted mice, IL-12 could not induce cytotoxic activity of liver and lung MNC and metastases in both organs increased with or without IL-12 treatment. These results confirmed the fact that NK+ int T cells are more potent antitumour effectors than NK cells against experimental haematogenous tumour metastases.

Animals↗

PubMed1997

Hepatic expression of c-Myb in chronic human liver disease.

C-Myb is a sequence-specific DNA binding protein that regulates the expression of genes involved in cell proliferation and differentiation. The present study was designed to elucidate the role of c-Myb in the pathogenesis of chronic liver disease by an immunohistochemical approach. In normal (control) livers, few or no hepatic cells were positive for c-Myb. In livers from patients with chronic viral hepatitis, positive staining for c-Myb was found not only in spindle-shaped mesenchymal cells in expanded portal areas, but also in perisinusoidal cells (PSCs) within liver lobules. In cirrhotic livers, a few PSCs within lobules were positive for c-Myb, while no staining was seen in fibrous septa. Immunoelectron microscopy revealed that c-Myb-positive PSCs displayed morphological features of hepatic stellate cells. Other sinusoidal lining cells including Kupffer cells and sinusoidal endothelial cells, as well as hepatocytes, were all negative for c-Myb. Dual c-Myb/alpha-smooth muscle actin (alphaSMA) staining revealed that more than 97% of c-Myb-positive cells were alphaSMA-positive. Moreover, dual c-Myb/proliferating cell nuclear antigen (PCNA) staining showed that approximately 70% of c-Myb-positive cells also expressed PCNA. The labeling index (LI) (number of c-Myb-positive cells/0.1 mm2) significantly correlated with serum transaminase concentrations and increased in parallel with the disease activity. However, the LI showed no correlation with the degree of fibrosis. These results suggest that c-Myb may be involved in stellate cell activation and proliferation in chronically diseased human livers, and that the level of c-Myb expression is associated with the activity of chronic hepatitis.

Actins↗

PubMed1997

Neonatal granulocytosis is a postpartum event which is seen in the liver as well as in the blood.

In a recent series of studies, we demonstrated that stress in humans and animals, with resultant sympathetic nerve strain, induces severe granulocytosis, because granulocytes carry adrenergic receptors on the surface. Because activated granulocytes produce free radicals and superoxides, they sometimes induce tissue damage if the stress is too strong or continuous. Human neonates are also known to show high levels of granulocytes in the peripheral blood. In this study, we investigated whether such neonatal granulocytosis are a stress-associated response at birth. Both human and mouse materials, before and after birth, were used. The number of leukocytes in the blood, as well as some other factors in the serum, were measured. Although levels of granulocytes were found to be low in fetal humans and mice, they increased sharply after birth. In parallel with this postpartal granulocytosis, transaminases in sera increased transiently. In reference to results of a transient elevation in the levels of catecholamines at birth in mice, all these phenomena resemble stress-associated responses. Indeed, fatty liver and hematopoietic destruction in the liver were also observed in mice and humans. At this time, the production of inducible nitric oxide synthase (iNOS) by granulocytes in the liver was evident. These results suggest that neonatal granulocytosis is a postpartum event which results from various stresses (e.g., oxygen stress) at birth. This event may be responsible for such well-known neonatal phenomena as the termination of fetal hematopoiesis in the liver and as neonatal jaundice.

Alanine Transaminase↗

PubMed1997

Halothane and enflurane attenuate pulmonary vasodilation mediated by adenosine triphosphate-sensitive potassium channels compared to the conscious state.

BACKGROUND: Adenosine triphosphate (ATP)-sensitive potassium (k+ATP) channels play an important role in pulmonary vasoregulation. However, the effects of volatile anesthetics on k+ATP channel-mediated pulmonary vasoregulation have not been elucidated. The purpose of the present study was to investigate the effects of halothane and enflurane anesthesia on the pulmonary vasodilator response to the selective k+ATP channel agonist lemakalim (BRJ38227) compared with that measured in the conscious state. The authors also investigated the extent to which endogenous neurohumoral vasoconstrictor mechanisms modulate the vasodilator response to k+ATP channel activation. METHOD: Nineteen conditioned, male mongrel dogs were chronically instrumented to measure the left pulmonary vascular pressure-flow (LPQ) relationship. LPQ plots were generated by continuously measuring the pulmonary vascular pressure gradient (pulmonary arterial pressure-left atrial pressure) and left pulmonary blood flow during gradula (approximately 1 min) inflation of a hydraulic occluder implanted around the right main pulmonary artery. After preconstriction with the thromboxane analog, U46619 (9,11-dideoxy-11 alpha, 9 alpha-epoxymethano-prostaglandin F2 alpha), the pulmonary vascular dose-response relationship for the k+ATP agonist lemakalim was assessed in the conscious and halothane-anesthetized states and also in the conscious and enflurane-anesthetized states. This protocol was repeated in conscious and halothane-anesthetized dogs after combined neurohumoral block with antagonists of sympathetic alpha 1 adrenoreceptors, arginine vasopressin V1-receptors, and angiotensin II receptors. The effect of the k+ATP antagonist glybenclamide on the baseline LPQ relationship and on the lemakalim dose-response relationship also was assessed in conscious dogs. RESULTS: Compared with the conscious state, halothane, enflurane and glybenclamide had no net effect on the baseline LPQ relationship. In contrast, halothane and enflurane attenuated (P < 0.05) the pulmonary vasodilator response to lemakalim compared with the conscious state. Glybenclamide also caused a rightward shift (P < 0.05) in the lemakalim dose-response relationship. Combined neurohumoral block did not modulate the vasodilator response to lemakalim in the conscious state. The halothane-induced attenuation of the vasodilator response to lemakalim was apparent after combined neurohumoral block. CONCLUSION: These results indicate that halothane and enflurane act to reduce the magnitude of K+ATP channel-mediated pulmonary vasodilation. Reflex pulmonary vasoconstriction resulting from K+ATP mediated systematic hypotension does not alter the magnitude of the pulmonary vasodilator response to lemakalim nor is it responsible for the attenuated response to K+ATP channel activation during halothane anesthesia.

Adenosine Triphosphate↗

PubMed1997

Halothane attenuates endothelium-dependent pulmonary vasorelaxant response to lemakalim, an adenosine triphosphate (ATP)-sensitive potassium channel agonist.

BACKGROUND: Lemakalim, an adenosine triphosphate (ATP)-sensitive potassium (K+(ATP)) channel agonist, causes profound pulmonary vasodilation in conscious dogs, which is attenuated during halothane anesthesia. The goal of the present study was to investigate the mechanism responsible for this attenuating effect of halothane. METHODS: Isolated canine pulmonary arterial rings were suspended for isometric tension recording in 25 ml organ baths. Rings with and without endothelium were contracted to 50% of their maximal response to phenylephrine, followed by the cumulative administration of lemakalim with or without exposure to halothane (0.5-1.5 minimum alveolar concentration [MAC] in dogs). Lemakalim dose-response curves were also generated in rings pretreated with the nitric oxide synthase inhibitor, Nw-nitro-L-arginine methyl ester (L-NAME); the cyclooxygenase inhibitor, indomethacin; or the K+(ATP) channel antagonist, glybenclamide. RESULTS: Compared with intact rings, the pulmonary vasorelaxant response to lemakalim was attenuated (P < 0.05) in endothelium-denuded rings. Halothane at 0.5 MAC had no effect on the vasorelaxant response to lemakalim. Halothane at 1 MAC attenuated (P < 0.05) the vasorelaxant response to lemakalim in intact rings, but not in endothelium-denuded rings. Halothane at 1.5 MAC attenuated (P < 0.05) the vasorelaxant response to lemakalim in both intact and endothelium-denuded rings. In endothelium-intact rings, indomethacin attenuated (P < 0.05) the vasorelaxant response to lemakalim, whereas L-NAME had no effect. Further, indomethacin, but not L-NAME, abolished the endothelium-dependent, halothane-induced attenuation of the lemakalim vasorelaxation response. Glybenclamide markedly attenuated (P < 0.05) lemakalim vasorelaxation at lemakalim doses less than 10(-6) M. CONCLUSIONS: Lemakalim-induced pulmonary vasorelaxation involves an endothelium-dependent and vascular smooth muscle component. Further, halothane attenuates the endothelium-dependent pulmonary vasorelaxant response to lemakalim via an inhibitory effect on vasodilator metabolites of the cyclooxygenase pathway.

Adenosine Triphosphate↗

PubMed1997

cDNA cloning, sequence analysis and expression of a mouse 44-kDa nuclear protein copurified with DNA repair factors for acid-depurinated DNA.

We purified a 44-kDa nuclear protein from salt-extract of permeable mouse ascites sarcoma cells in an effort to isolate factors involved in the repair of acid-depurinated DNA. It was copurified with a major AP endonuclease (APEX nuclease) by sequential column chromatography then further purified by sodium dodecyl sulphate-polyacrylamide gel electrophoresis as a possible DNA repair support factor. Its partial amino acid sequences were determined, and a cDNA clone for the protein was isolated from a mouse T-cell cDNA library using long degenerate oligonucleotide probes deduced from the amino acid sequence. The complete nucleotide sequence of the cDNA (1.7 kilobases) was determined. Northern hybridization using this cDNA detected two transcripts: 1.8 kb being the major one and 2.6 kb being the minor one. The complete amino acid sequence for the protein predicted from the nucleotide sequence of the cDNA indicates that the 44-kDa protein consists of 394 amino acids with a calculated molecular weight of 43,698. In tests performed thus far, the recombinant 44-kDa protein expressed in Escherichia coli has not expressed any repair-support activity. It remains to be analyzed whether the protein attains this activity after appropriate posttranslational modifications. Most parts of the 44-kDa protein cDNA and the deduced amino acid sequence were found to be identical to those of the protein p38-2G4, recently reported as a cell cycle-specifically modulated nuclear protein of 38kDa. The p38-2G4 may be a truncated form of the present 44-kDa protein.

Amino Acid Sequence↗