Possible liver damage by biosynthetic human insulin.
Explore the source record for details and available documents.
Chemical and Drug Induced Liver Injury↗
Biomedical subjects
N Sato
Publications and source records attributed to N Sato.
A novel presenilin-2 splice variant in human Alzheimer's disease brain tissue.
Mutations in the presenilin-1 (PS-1) and presenilin-2 (PS-2) genes account for the majority of cases of early-onset familial Alzheimer's disease (AD). Alternative splicing forms of the PS-1 and PS-2 gene products have previously been reported in fibroblast and brain tissue from both familial and sporadic AD patients, as well as from normal tissues and cell lines. We demonstrate here unusual alternative splicing of the PS-2 gene that leads to the generation of mRNA lacking exon 5 in human brain tissue. This product was more frequently detected in brain tissue from sporadic AD patients (70.0%; 21 of 30) than from normal age-matched controls (17.6%; three of 17). In cultured neuroblastoma cells, this splice variant was generated in hypoxia but not under other forms of cellular stress. Hypoxia-mediated induction of this splice variant was blocked by pretreatment of neuroblastoma cells with the protein synthesis inhibitor cycloheximide or antioxidants such as N-acetylcysteine and diphenyl iodonium, suggesting that hypoxia-mediated oxidant stress might, at least in part, underlie the alternative splicing of PS-2 mRNA through de novo protein synthesis. Furthermore, the stable transfectants of this splice variant produced the N-terminal part of PS-2 protein (15 kDa) and were more susceptible to cellular stresses than control transfectants. These results suggest the possibility that altered presenilin gene products in stress conditions may also participate in the pathogenesis of AD.
Aged↗
Faropenem enhances superoxide anion production by human neutrophils in vitro.
Neutrophils are important cellular components in the defence against infections and many studies in vitro have shown that some antibiotics affect neutrophil function. We examined the effect of faropenem, a new oral penem antibiotic on neutrophil killing function by determining the generation of superoxide anion in vitro. The production of superoxide anion was measured by chemiluminescence amplified by a Cypridina luciferin analogue in the presence of N-formyl-Met-Leu-Phe (fMLP). Faropenem significantly enhanced chemiluminescence in a dose-dependent manner. The effect of faropenem was maximal at 5 min of incubation time and continued for at least 30 min. The effect of faropenem was also observed when neutrophils were stimulated by a calcium ionophore (ionomycin), while the effect of faropenem did not change in the presence of 12-O-tetra-decanoylphorbolmyristate acetate. Cytosol Ca2+ concentration ([Ca2+]i) monitored with Fura-2 increased in response to fMLP, however, faropenem did not influence the response of [Ca2+]i to fMLP. Our results suggest that faropenem enhanced the generation of superoxide anion by neutrophils, probably at the site where cytosol Ca2+ regulates NADPH oxidase. Faropenem might be potentially advantageous in the treatment of infections because a synergic interaction of antibodies and cytocidal neutrophils is necessary for the early eradication of the pathogenic bacteria.
Anti-Bacterial Agents↗
Analysis of where and which types of proteinases participate in lysosomal proteinase processing using bafilomycin A1 and Helicobacter pylori Vac A toxin.
Lysosomal proteinases are translated as preproforms, transported through the Golgi apparatus as proforms, and localized in lysosomes as mature forms. In this study, we analyzed which subclass of proteinases participates in the processing of lysosomal proteinases using Bafilomycin A1, a vacuolar ATPase inhibitor. Bafilomycin A1 raises lysosomal pH resulting in the degradation of lysosomal proteinases such as cathepsins B, D, and L. Twenty-four hours after the withdrawal of Bafilomycin A1, NIH3T3 cells possess these proteinases in amounts and activities similar to those in cells cultured in DMEM and 5% BCS. In the presence of various proteinase inhibitors, procathepsin processing is disturbed by E-64-d, resulting in abnormal processing of cathepsins D and L, but not by APMSF, Pepstatin A, or CA-074. In the presence of Helicobacter pylori Vac A toxin, which prevents vesicular transport from late endosomes to lysosomes, the processing of procathepsins B and D occurs, while that of procathepsin L does not. Thus, procathepsins B and D are converted to their mature forms in late endosomes, while procathepsin L is processed to the mature form after its arrival in lysosomes by some cysteine proteinase other than cathepsin B.
3T3 Cells↗
A part of the transmembrane domain of pro-TNF can function as a cleavable signal sequence that generates a biologically active secretory form of TNF.
To determine the minimum requirement in the 76-residue leader sequence of pro-tumor necrosis factor (TNF) for membrane translocation across the endoplasmic reticulum (ER) and for the maturation of pro-TNF, we constructed pro-TNF mutants in which a part of the transmembrane domain of pro-TNF was directly linked to the N-terminus of the mature domain, and evaluated their translocational behavior across the ER-membrane and their secretion from the transfected cells. The in vitro translation/translocation assay involving a canine pancreatic microsomal membrane system including a mutant, Delta-75-47, -32-1, revealed that the N-terminal half of the transmembrane domain of pro-TNF consisting of 14 residues functioned as a cleavable signal sequence; it generated a cleaved form of TNF having a molecular mass similar to that of mature TNF. Analysis of the cleavage site by site-directed mutagenesis indicated that the site was inside the leader sequence of this mutant. When the mutant, Delta-75-47, -32-1, was expressed in COS-1 cells, efficient secretion of a biologically active soluble TNF was observed. Further deletion of the hydrophobic domain from this mutant inhibited the translocation, indicating that some extent of hydrophobicity is indispensable for the membrane translocation of the mature domain of TNF. Thus, the N-terminal half of the transmembrane domain of pro-TNF could function as a cleavable signal sequence when linked to the mature domain of TNF, and secretion of a biologically active secretory form of TNF could be achieved with this 14-residue hydrophobic segment. In intact pro-TNF, however, this 14-residue sequence could not function as a cleavable signal sequence during intracellular processing, indicating that the remainder of the 76-residue leader sequence of pro-TNF inhibits the signal peptide cleavage and thus enables the leader sequence to function as a type II signal-anchor sequence that generates a transmembrane form of TNF.
Animals↗
Autoimmune pancreatitis with F-18 fluoro-2-deoxy-D-glucose PET findings
Two cases of pancreatitis induced by autoimmunity with PET images using F-18 fluoro-2-deoxy-D-glucose (FDG) are reported. The patients had abdominal pain and were thought to have possible pancreatic neoplasms. In one patient, PET showed intense uptake of the entire pancreas, but a Ga-67 scan yielded a negative result. Because the serum immunoglobulin G level was high, autoimmune pancreatitis was diagnosed in this patient. He underwent steroid therapy and fully recovered. In another patient with positive antinuclear antibodies and hyperglobulinemia, focal intense uptake was found in the head of the pancreas on the FDG PET. She also recovered with steroid therapy. Autoimmune pancreatitis is a relatively new form of chronic pancreatitis and should be kept in mind when making a differential diagnosis of pancreatic cancer with the assistance of FDG PET.
Journal Article↗
A novel negative regulator molecule, Cho-1, is involved in the cytotoxicity by human natural killer cells but not in cytotoxic T lymphocytes.
We previously reported the cytotoxic negative regulatory molecule, Cho-1, that was expressed on the cell surface of rat fetal fibroblast cells in the cytotoxicity by natural killer (NK) cells. This molecule was IFN-gamma-inducible, but appeared to be different from MHC class I. It was expressed on NK-resistant cells but not on NK-sensitive murine target cells such as YAC-1. In this paper, first we determined whether Cho-1 could also act as the negative regulatory molecule in a human NK-resistant HEPM line. Our data strongly suggested that Cho-1 could act as such a negative regulatory molecule in human NK cytotoxicity. The immunoprecipitates made with HEPM cell lysate and anti-MHC class I monoclonal antibody (mAb) did not react against anti-Cho-1 mAb, indicating that Cho-I was different from MHC class I. Second, an assessment was made as to whether or not this molecule is involved in the cytotoxicity of CD8 (+) cytotoxic T lymphocytes (CTL) against human autologous tumor cells. The data indicated that although this cell surface molecule was expressed on certain tumor lines, it was not involved in the cytotoxic mechanism of CTL. Thus, Cho-1 appeared to be the novel regulatory molecule in the NK cytotoxic mechanism.
Animals↗
Frequent p53 gene mutations in soft tissue sarcomas arising in burn scar.
Squamous cell carcinoma (SCC) is the commonest malignancy that arises in burn scars, which frequently contain p53 mutations. Soft tissue sarcoma (STS) also develops, though less frequently, in burn scars. p53 gene mutations were analyzed in paraffin-embedded specimens from 5 patients with STS (4 males and 1 female) that had arisen in a burn scar, by means of polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) followed by direct sequencing. Age at burn injury ranged from 2 to 10 (median 3) years, and STS developed with a latent period ranging from 29 to 79 (median 60) years. Histologically, all were malignant fibrous histiocytoma. The PCR-SSCP revealed aberrant bands in 4 (80%) of 5 cases. Direct sequencing revealed a total of 11 mutations in these 4 cases: 1 case had a single mutation, 1 had 2 mutations, and 2 had 4 mutations. Every tumor had at least 1 mutation that changed an amino acid, which may have provided the selection pressure for expansion. Thus, there is a high frequency of p53 gene mutations in STS appearing in burn scars. p53 mutations were also frequent in pyothorax-associated lymphoma (PAL), a lymphoma that develops in patients with long-standing pyothorax, so p53 mutations might be frequent in malignancies that develop in chronic inflammatory sites.
Adult↗
Radioimmunotherapy for liver micrometastases in mice: pharmacokinetics, dose estimation, and long-term effect.
The pharmacokinetics of a therapeutic dose of 131I-labeled antibody and the absorbed dose in liver micrometastases of human colon cancer LS174T in female BALB/c nu/nu mice were investigated, along with the long-term therapeutic effect. Mice with liver micrometastases were given an intravenous injection of 131I-labeled anti-carcinoembryonic antigen (CEA) antibody F33-104 (8.88 MBq/ 40 microg). The biodistribution of the antibody was determined 1, 2, 4, 6, and 10 days later. The absorbed dose was estimated for three hypothetical tumor diameters; 1,000, 500, and 300 microm. Autoradiography showed a homogeneous distribution of radioactivity in the micrometastases, and a high uptake was maintained until day 6 (24.0 % injected dose (ID)/g on day 1 to 17.8 %ID/g on day 6), but decreased thereafter. The absorbed doses in the 1,000-, 500-, and 300-microm tumors were calculated to be 19.1, 12.0, and 8.2 Gy, respectively. The intravenous injection of the 131I-labeled antibody also showed a dose-dependent therapeutic effect (all mice of the nontreated group died, with a mean survival period of 4 weeks; 3 of the 8 mice that received 9.25 MBq survived up to 120 days with no sign of liver metastasis). These data give further evidence that micrometastasis is a good target of radioimmunotherapy, and that an absorbed dose of less than 20 Gy can effectively control small metastatic lesions.
Animals↗
How useful is the detection kit for antibody to Helicobacter pylori in urine (URINELISA) in clinical practice?
OBJECTIVE: Increased knowledge of the significance of Helicobacter pylori (H. pylori) infection in gastric disorders has accelerated the trend of screening patients with dyspepsia for its infection. Serological examination of antibody for H. pylori has been widely performed. Recently, a urine-based enzyme-linked immunosorbent assay (URINELISA) kit for detection of antibody for H. pylori has been developed. Accordingly, we evaluated its diagnostic accuracy in clinical practice. METHODS: Subjects of this study were 132 patients who presented at our university hospital because of dyspeptic symptoms (81 men, 51 women; age, 41.5+/-1.4 yr). 13C urea breath test, blood drawing for serological antibody for H. pylori infection by four different kits, and urine collection for the URINELISA test for detection of the antibody were performed. Diagnostic accuracy of the commercially available antibodies in serum and in urine were investigated using the results of the 13C urea breath test as the gold standard. RESULTS: Sensitivity, specificity, and accuracy of URINELISA were 86.3% (95% confidence intervals [CI], 76-93%), 91.5% (95% CI, 81-97%), and 88.6% (95% CI, 82-93%), respectively, which were comparable to those of imported serological kits. CONCLUSIONS: The URINELISA kit for detecting anti-H. pylori antibody in urine provides diagnostic accuracy comparable to that of imported kits for detecting antibodies in serum and is considered to be clinically useful for the diagnosis of H. pylori infection.
Adult↗
A novel growth- and cell cycle-regulated protein, ASK, activates human Cdc7-related kinase and is essential for G1/S transition in mammalian cells.
A novel human protein, ASK (activator of S phase kinase), was identified on the basis of its ability to bind to human Cdc7-related kinase (huCdc7). ASK forms an active kinase complex with huCdc7 that is capable of phosphorylating MCM2 protein. ASK appears to be the major activator of huCdc7, since immunodepletion of ASK protein from the extract is accompanied by the loss of huCdc7-dependent kinase activity. Expression of ASK is regulated by growth factor stimulation, and levels oscillate through the cell cycle, reaching a peak during S phase. Concomitantly, the huCdc7-dependent kinase activity significantly increases when cells are in S phase. Furthermore, we have demonstrated that ASK serves an essential function for entry into S phase by showing that microinjection of ASK-specific antibodies into mammalian cells inhibited DNA replication. Our data show that ASK is a novel cyclin-like regulatory subunit of the huCdc7 kinase complex and that it plays a pivotal role in G1/S transition in mammalian cells.
Amino Acid Sequence↗
Effect of mechanical strain on gastric cellular migration and proliferation during mucosal healing: role of Rho dependent and Rac dependent cytoskeletal reorganisation.
BACKGROUND: Various factors affect gastric wound healing. The influence of physical stimulation on gastric mucosal cells during the process of gastric wound healing is not completely understood. AIMS: To assess the role of a physical stimulant, in this case mechanical strain, on gastric mucosal restoration. METHODS: Mechanical strain was applied to adherent rat gastric mucosal cells (RGM1) cultured confluently on collagen type I coated silicone elastomer membrane in order to increase the dimension by an average of 5% and 10% at 5 cycles/minute for 72 hours after wounding. Repair of the wound was monitored every 12 hours for up to 72 hours using an inverted phase contrast microscope. Cell proliferation was detected using 5-bromodeoxyuridine staining. The cytoskeletal protein actin, a component of focal adhesion plaque protein, vinculin, and the small GTP-binding proteins RhoA and Rac1 were detected by immunohistochemistry in the cells located at the margin of and remote from the wound. RESULTS: The cells located at the margin of the wound showed the greatest migration and proliferation and were found to express more rudimentary lamellipodia and filopodia in the absence of mechanical strain. Vinculin, RhoA, and Rac1 were also strongly expressed in the wound margin. Under conditions of mechanical strain, the speed of migration of cells slowed and fewer proliferating cells were detected around the wound in a strain strength dependent manner. Lamellipodial formation, vinculin, RhoA, and Rac1 were poorly expressed in the same area. However, in cells located more than 1 mm from the wound edge, cytoskeletal rearrangement, and the expression of vinculin, RhoA, and Rac1 were not influenced by mechanical strain. CONCLUSIONS: Migration and proliferation of RGM1 cells in culture during wound healing were inhibited by mechanical strain, which caused dysfunction of the cytoskeletal and cell adhesion systems. It is suggested that physical stimulants such as mechanical strain may play a role in gastric wound healing in vivo by modifying cellular migration and proliferation.
Animals↗
Expression and localization of aquaporins in rat gastrointestinal tract.
A family of water-selective channels, aquaporins (AQP), has been demonstrated in various organs and tissues. However, the localization and expression of the AQP family members in the gastrointestinal tract have not been entirely elucidated. This study aimed to demonstrate the expression and distribution of several types of the AQP family and to speculate on their role in water transport in the rat gastrointestinal tract. By RNase protection assay, expression of AQP1-5 and AQP8 was examined in various portions through the gastrointestinal tract. AQP1 and AQP3 mRNAs were diffusely expressed from esophagus to colon, and their expression was relatively intense in the small intestine and colon. In contrast, AQP4 mRNA was selectively expressed in the stomach and small intestine and AQP8 mRNA in the jejunum and colon. Immunohistochemistry and in situ hybridization demonstrated cellular localization of these AQP in these portions. AQP1 was localized on endothelial cells of lymphatic vessels in the submucosa and lamina propria throughout the gastrointestinal tract. AQP3 was detected on the circumferential plasma membranes of stratified squamous epithelial cells in the esophagus and basolateral membranes of cardiac gland epithelia in the lower stomach and of surface columnar epithelia in the colon. However, AQP3 was not apparently detected in the small intestine. AQP4 was present on the basolateral membrane of the parietal cells in the lower stomach and selectively in the basolateral membranes of deep intestinal gland cells in the small intestine. AQP8 mRNA expression was demonstrated in the absorptive columnar epithelial cells of the jejunum and colon by in situ hybridization. These findings may indicate that water crosses the epithelial layer through these water channels, suggesting a possible role of the transcellular route for water intake or outlet in the gastrointestinal tract.
Animals↗
Mechanisms of desensitization to a PDE inhibitor (milrinone) in conscious dogs with heart failure.
The goal of this study was to determine the extent to which the effects of milrinone were desensitized in heart failure (HF) and to determine the mechanisms, i.e., whether these effects could be ascribed to changes in cAMP or phosphodiesterase (PDE) activity in HF. Accordingly, we examined the effects of milrinone in seven conscious dogs before and after HF was induced by rapid ventricular pacing at 240 beats/min. The dogs were chronically instrumented for measurements of left ventricular (LV) pressure and first derivative of LV pressure (dP/dt), arterial pressure, LV internal diameter, and wall thickness. Milrinone (10 micrograms . kg-1. min-1 iv) increased LV dP/dt by 1,854 +/- 157 from 2,701 +/- 105 mmHg/s (P < 0.05) before HF. After HF the increase in LV dP/dt in response to milrinone was attenuated significantly (P < 0.05); it increased by 615 +/- 67 from 1,550 +/- 107 mmHg/s, indicating marked desensitization. In the presence of ganglionic blockade the increases in LV dP/dt (+445 +/- 65 mmHg/s) in response to milrinone were markedly less (P < 0.01), and milrinone increased LV dP/dt even less in HF (+240 +/- 65 mmHg/s). cAMP and PDE activity were measured in endocardial and epicardial layers in normal and failing myocardium. cAMP was decreased significantly (P < 0.05) in LV endocardium (-26%) but not significantly in LV epicardium (-14%). PDE activity was also decreased significantly (P < 0.05) in LV endocardium (-18%) but not in LV epicardium (-4%). Thus significant desensitization to milrinone was observed in conscious dogs with HF. The major effect was autonomically mediated. The biochemical mechanism appears to be due in part to the modest reductions in PDE activity in failing myocardium, which, in turn, may be a compensatory mechanism to maintain cAMP levels in HF. Reductions in cAMP and PDE levels were restricted to the subendocardium, suggesting that the increased wall stress and reduced coronary reserve play a role in mediating these changes.
Animals↗
Nitric oxide differentially attenuates microvessel response to hypoxia and hypercapnia in injured lungs.
The issue of whether the acinar microvessel response to alveolar hypoxia and hypercapnia is impaired in injured lungs has not been vigorously addressed, despite the importance of knowing whether it is or not when treating patients with serious lung injury in terms of permissive hypercapnia. Applying a real-time laser confocal luminescence microscope, we studied hypoxia- and hypercapnia-induced changes in the diameter of the intra-acinar arterioles, venules, and capillaries of isolated rat lungs harvested from animals exposed for 48 h to 21% O(2) (group N) or 90% O(2) (group H). Measurements were made with and without inhibition of nitric oxide (NO) synthase (NOS) by N(omega)-nitro-L-arginine methyl ester or of cyclooxygenase (COX) by indomethacin at different basal vascular tones evoked by thromboxane A(2) (TXA(2)) analog. Hypoxia in the absence of TXA(2) contracted arterioles in group N but not in group H. Attenuated hypoxia-induced arteriole constriction was restored almost fully by inhibiting NOS and partially by inhibiting COX. Hypercapnia induced venule dilation in group N, but did not dilate venules in group H, irrespective of TXA(2). NOS inhibition in hypercapnia unexpectedly enhanced venule and arteriole dilation in group H. These responses no longer occurred when NOS and COX were inhibited simultaneously. In conclusion, microvessel reactions to hypoxia and hypercapnia are abnormal in hyperoxia-injured acini, in which NO directly attenuates hypoxia-induced arteriole constriction, whereas COX inhibited by excessive NO impedes hypercapnia-induced microvessel dilation.
Animals↗
Genomic organization and chromosome location of the rat CD3zeta locus (Cd3z).
The structure and pattern of expression of the CD3zeta chain have apparently been conserved throughout mammalian evolution. The organization of the rat CD3zeta locus was determined by genomic cloning and nucleotide sequencing. Most of the rat CD3zeta coding region was similar to mouse and human CD3zeta sequences. Whereas the 3' region involving alternative splicing was relatively well conserved at the nucleotide level, the deduced amino acid sequences were different in rats, mice and humans due to the presence of deletion and insertion mutations. Alternative splicing products of the CD3zeta locus, such as CD3eta, CD3θ and CD3tau, which have been reported for mice, were not expressed by rat T cells. By using fluorescence in situ hybridization, we have localized rat CD3zeta to chromosome 13q22-->q23.
Alternative Splicing↗
Correction and confirmation of the assignment of Cd1d the evolutionarily conserved CD1D class gene to rat chromosome 2q34 and its relationship to human and mouse loci.
Explore the source record for details and available documents.
Animals↗
Induction of the hair growth phase in postnatal mice by localized transient expression of Sonic hedgehog.
Hair follicles form in prenatal skin and mature in the postnatal period, establishing a growth cycle in 3 phases: telogen (resting), anagen (growth), and catagen (regression). Based on the knowledge that Sonic hedgehog (Shh) expression is necessary for the embryonic development of hair follicles, and that anagen in the postnatal cycling follicle has morphologic similarities to the epithelial invagination process in embryonic skin, we hypothesized that localized, but transient, enhanced expression of the Shh gene in postnatal skin would accelerate initiation of anagen in the hair follicle cycle, with concomitant accelerated hair growth. To assess this concept, an E1(-) adenovirus vector, AdShh, was used to transfer the murine Shh cDNA to skin of postnatal day 19 C57BL/6 mice. The treated skin showed increased mRNA expression of Shh, Patched (the Shh receptor), and Gli1 (a transcription factor in the Shh pathway). In mice receiving AdShh, but not in controls, acceleration into anagen was evident, since hair follicle size and melanogenesis increased and the hair-specific keratin ghHb-1 and the melanin synthesis-related tyrosinase mRNAs accumulated. Finally, C57BL/6 mice showed marked acceleration of the onset of new hair growth in the region of AdShh administration to skin 2 weeks after treatment, but not in control vector-treated or untreated areas. After 6 months, AdShh-treated skin showed normal hair and normal skin morphology. Together, these observations are consistent with the concept that upregulation of Shh activity in postnatal skin functions as a biologic switch that induces resting hair follicles to enter anagen with consequent hair growth.
Adenoviridae↗