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K Fujiwara

Publications and source records attributed to K Fujiwara.

At least 541 records · Page 30Linked to original sources
PubMed1991

Minor contribution of hepatocytes to collagen production in normal and early fibrotic rat livers.

Hepatocyte contribution to hepatic collagen production in vivo was estimated in rats, based on the fact that ornithine is used for protein synthesis in the liver as arginine after conversion by way of the urea cycle only by hepatocytes. From rats given a mixture of [14C] ornithine and [3H]arginine, hepatic collagen and serum albumin were obtained. The hepatocyte contribution was calculated from the 14C and 3H in arginine purified from collagen and albumin by high performance liquid chromatography. The contribution was less than 10% of total collagen production in normal and early fibrotic livers induced by a single dose of carbon tetrachloride or dimethylnitrosamine. We conclude that hepatocytes may play a minor role in collagen production in normal and early fibrotic rat livers.

Amino Acids↗
PubMed1991

[The anesthetic management of a patient with the malignant hyperthermia trait diagnosed preoperatively].

A patient for fixation of ankle arthrodesis diagnosed as having malignant hyperthermia trait preoperatively is reported. A 17 year old man was anesthetized with enflurane for orthopedic surgery of the knee joint. At that time malignant hyperthermia developed. He was critically ill, but resuscitated and recovered from acute renal failure on 7th day after operation. Ca2+ release test was performed. Ca2+ releasing speed was prominently accelerated in this patient. We could identify him as having malignant hyperthermia trait. Epidural anesthesia with procaine chloride was given cautiously. No drug which may induce malignant hyperthermia was used. Nevertheless, malignant hyperthermia occurred. This disease has various forms of presentation. The mechanism is equivocal, and in some cases, it is difficult to judge it immediately. This patient was managed without complication. We consider that tourniquet and stress provoked signs of malignant hyperthermia in this patient.

Adolescent↗
PubMed1991

[An autopsy case of adult respiratory distress syndrome (ARDS) with peculiar histopathological features modified by a positive end-expiratory pressure (PEEP) therapy].

A case is reported of adult respiratory distress syndrome(ARDS) combined with barotrauma due to positive end-expiratory pressure (PEEP) therapy. The patient was a 32-year-old woman with fulminant hepatitis, type B, who died of ARDS 22 days after the onset of the illness. The autopsy revealed extraordinary heavy lungs (left: 923g, right: 985g) with edema in the peripheral part and marked emphysematous changes in the central part near the hili. Histologically, scattered foci of intra-alveolar organization and interstitial fibrosis with hemorrhage were observed, which might have been the result of the proceeding pneumonia. The emphysematous lesion seen in this case was peculiar and not like any type of of ordinary pulmonary emphysema. Judging from the strange, sharply demarcated emphysematous lesion with marked destruction of alveolar structure, and the good preservation of the alveolar structure in the edematous lesion, the emphysematous lesion might be barotrauma which was induced by PEEP therapy on top of pneumonia.

Adult↗
PubMed1991

[Cell adhesion and the cytoskeleton].

Most cells have macromolecules on their outer surface that are specialized for adhesion. Cells can attach to another cell and/or various extracellular matrix components. When tissue culture cells attach to the substrate, they form a specialized structure called adhesion plaque. At the cytoplasmic side of the adhesion plaque, stress fibers terminate, forming an electron-dense plasma membrane undercoat structure. Integrin is localized to the adhesion plaque and this is a transmembrane protein that connects the cytoskeleton to the extracellular matrix. Endothelial cells in vivo have stress fibers, and we have recently found that the ends of these stress fibers also terminate at a structure similar to the adhesion plaque of cultured cells. It appears, therefore, that endothelial cells in vivo employ similar, if not identical, mechanism for adhesion as the one used by tissue culture cells.

Animals↗
PubMed1990

Suppression mutations in the defective beta subunit of F1-ATPase from Escherichia coli.

The Escherichia coli mutant of the proton-translocating ATPase KF11 (Kanazawa, H., Horiuchi, Y., Takagi, M., Ishino, Y., and Futai, M. (1980) J. Biochem. (Tokyo) 88, 695-703) has a defective beta subunit with serine being replaced by phenylalanine at codon 174. Four suppression mutants (RE10, RE17, RE18, and RE20) from this strain capable of growth on minimal plate agar supplemented by succinate were isolated. The original point mutation at codon 174 was intact in these strains. Additional point mutations, Ala-295 to Thr, Gly-149 to Ser, Leu-400 to Gln, Ala-295 to Pro, for RE10, RE17, RE18, and RE20, respectively, were identified by the polymerase chain reaction and sequencing. These mutations, except for RE10, were confirmed as a single mutation conferring a suppressive phenotype by genetic suppression assay using KF11 as the host cells. The results indicated that Ser-174 has functional interaction with Gly-149, Ala-295, and Leu-400. The residues are located within the previously estimated catalytic domain of the beta subunit, indicating that this domain is indeed folded for the active site of catalytic function. Growth rates of the revertants in the minimal medium with succinate increased compared with that of KF11, showing that ATP synthesis recovered to some extent. The ATP hydrolytic activity in the revertant membranes increased in RE17 and RE20 but did not in RE10 and RE18, suggesting that synthesis and hydrolysis are not necessarily reversible in the proton-translocating ATPase (F1F0).

Amino Acid Sequence↗
PubMed1990

The use of N-(aminobenzoyloxy) succinimide as a two-level heterobifunctional agent for the preparation of hapten-protein conjugates. Daunomycin as a model hapten with an amino group.

Three geometric ortho-, meta-, and para-isomers of N-(aminobenzoyloxy)succinimide (ABS) were synthesized, and their usefulness as a two-level heterobifunctional cross-linking agent in the preparation of hapten-protein conjugates was evaluated. The conjugation was based on the principle that ABS reacts immediately with an amino group of a hapten, and an aminobenzoyl group incorporated into the hapten is then activated by diazotization to a functional diazobenzoyl group acting on tyrosine or histidine residues of the protein. Using the anti-tumor antibiotic daunomycin (DM) as a model hapten, the three isomers of ABS were compared for their ability to conjugate DM with bovine serum albumin (BSA); DM incorporation onto a BSA molecular was found to occur to the highest degree with m-ABS, followed by p-ABS. while o-ABS completely failed to conjugate under the same coupling conditions. Using m-ABS it was possible to introduce more than 10 molecules of DM per BSA molecule. One of the DM-BSA samples was used as the immunogen for the production of anti-DM serum in a rabbit. The antibody specificity was shown to be direct to DM but not to other anti-cancer drugs (bleomycin, mitomycin C, actinomycin D and 5-fluorouracil) by the double antibody enzyme immunoassay (DEIA) using DM-beta-galactosidase conjugate as a label. An enzyme-linked immunosorbent assay (ELISA) for anti-DM IgG was developed using a DM-human serum albumin (DM-HSA) conjugate similarly prepared with m-ABS and horseradish peroxidase-conjugated goat anti-rabbit IgG as the solid-phase antigen and the labelled second antibody, respectively. This ELISA permitted us to measure accurately as little as 50 ng of anti-DM IgG per ml using a standard anti-DM IgG which had been purified from the anti-DM serum using an affinity column of Sepharose 4B with DM-HSA as the ligand. Using this ELISA as well as a sandwich enzyme immunoassay (SEIA) for total IgG, serum levels of anti-DM IgG and total IgG levels were easily monitored in a rabbit following immunization with DM-BSA. These results indicate that the use of DBS provides a novel method for preparing hapten-protein conjugates which will be useful in biochemistry and immunochemistry.

Acetylation↗
PubMed1990

Lys-65 and Glu-168 are the residues for carbodiimide-catalyzed cross-linking between the two heads of rigor smooth muscle heavy meromyosin.

We have previously demonstrated that the two heads of chicken gizzard heavy meromyosin (HMM) in a rigor complex with rabbit skeletal F-actin could be cross-linked by the water-soluble carbodiimide 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide. Here, we report the location of the cross-linked sites in the amino acid sequence of the HMM heavy chain. One of the cross-linked residues was identified as Glu-168 by sequencing the CN1.CN6 cross-linked peptide containing residues 1-77 (CN1) and 164-203 (CN6). This site is located close to the ATP-binding site of HMM. Since the other site was further into the amino acid sequence of CN1, another cross-linked peptide corresponding to residues 53-66 and 145-182 was isolated from the 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide-treated acto-tryptic gizzard HMM digested further by other proteolytic enzymes. The amino acid sequence of this peptide and its cyanogen bromide fragment indicated that the cross-linking occurred between Glu-168 and Lys-65. Our results suggests that these two amino acid side chains are in contact with each other in the acto-gizzard HMM rigor complex and participate in the electrostatic interaction between the two HMM heads bound to F-actin. Based on the head-to-head contact, we propose a three-dimensional model for the attachment of gizzard HMM heads to F-actin.

Actins↗
PubMed1990

cDNA sequence, in vitro synthesis, and intramitochondrial lipoylation of H-protein of the glycine cleavage system.

H-protein is a component of the glycine cleavage system loosely associated with the mitochondrial inner membrane and has lipoic acid as a prosthetic group. cDNA clones encoding H-protein were isolated from a bovine liver cDNA library with an oligonucleotide probe from the amino acid sequence of the NH2-terminal region. DNA sequence analysis and deduced amino acid sequence showed that the cDNAs encoded an H-protein precursor of 173 amino acids including a 48-amino acid presequence. Calculated molecular mass of the precursor and mature protein without lipoic acid were 18,790 and 13,846, respectively. Northern blot analysis indicated a major mRNA component of 1.1 kilobases and a minor component of 0.6 kilobase. The result is consistent with the presence of two adenylation signals in the 3'-untranslated region of the cDNA. In vitro transcription and translation of the H-protein cDNA produced a 19-kDa protein recognized by antibody raised to chicken H-protein. Bovine liver H-protein precursor has no lipoic acid prosthetic group. When incubated with isolated bovine liver mitochondria, the precursor was imported into mitochondria, processed to its mature form with a molecular mass of 14 kDa, and lipoylated at lysine 59. These results indicate that lipoylation is not required for the import of H-protein precursor into mitochondria and H-protein is lipoylated in mitochondria which probably contain the physiologically active form of lipoic acid as well as the enzyme(s) responsible for the attachment.

Amino Acid Sequence↗
PubMed1990

Possible contribution of protein kinase C activation to priming for DNA synthesis induced by epidermal growth factor with insulin and its inhibition by plasma membrane in primary cultured rat hepatocytes.

In primary cultured rat hepatocytes, DNA synthesis was markedly induced 48 h after plating by epidermal growth factor (EGF) and insulin added at 24 h, but not by 12-O-tetradecanoyl-phorbol-13-acetate (TPA). When EGF and insulin were added at 6 h, DNA synthesis at 30 h was 7% of DNA synthesis seen at 48 h, but became 27% by pretreatment with TPA. The similar pretreatment effect was also seen with vasopressin. Such induction at 30 h was inhibited by rat liver plasma membrane added at 2 h even in the presence of TPA or vasopressin, and also by 1-(5-isoquinolinyl-sulfonyl)-2-methylpiperazine more extensively than N-(2-guanidinoethyl)-5-isoquinolinesulfonamide. These results suggest that DNA synthesis induction by EGF and insulin may require a priming period related to protein kinase C activation in primary cultured rat hepatocytes, which is inhibited by plasma membrane.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1990

[MR imaging of compressive cervical myelopathy after surgery--high signal intensity of the spinal cord on T2 weighted images].

We reviewed the MR images of 32 patients with cervical myelopathy, showing lesions of high signal intensity in the spinal cord on the sagittal T2 weighted images (T2WI) after surgery: 16 with OPLL; 9 with spondylosis; 4 with disc herniation and 3 with trauma. All images were obtained on a superconducting 1.5 Tesla system. The lesions were classified into five groups, according to the shape and grade of signal intensity on the sagittal T2WI: (I) oval-shaped lesion of signal intensity less brighter than CSF with blurred margin, (II) longitudinal linear-shaped lesion of signal intensity similar to CSF, (III) spindle-shaped lesion of signal intensity similar to CSF, (IV) round-shaped lesion of signal intensity similar to CSF and (V) mixed-types lesions which consisted of group I and II. The present study was summarized as follows: 1) Oval-shaped lesions were seen in the cases of disc herniation and spondylosis with relatively short duration of the symptom, presumptively with relatively short duration of the symptom, presumptively indicative of edema. 2) Most cases of OPLL and spondylosis showed linear-shaped lesions, suggesting necrosis and/or cavitations of the central gray matter. 3) One case of spondylosis developed a spindle-shaped lesion, implicating syringomyelia. 4) Round-shaped lesions were seen in the cases of spinal trauma, suggesting posttraumatic cyst. 5) In a case of mixed-typed lesion examined pre- and postoperatively, only an oval-shaped lesion decreased in size after surgery.

Adult↗
PubMed1990

The rigor configuration of smooth muscle heavy meromyosin trapped by a zero-length cross-linker.

When chicken gizzard heavy meromyosin (HMM) in its rigor complex with actin was reacted with the zero-length cross-linker 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide (EDC), HMM cross-linked with actin but also the two heads of the HMM molecule cross-linked to each other [Onishi, H., Maita, T., Matsuda, G., & Fujiwara, K. (1989) Biochemistry 28, 1898-1904, 1905-1912]. By ultracentrifugal fractionation of the EDC-treated acto-HMM in the presence of Mg-ATP, we obtained a preparation enriched for gizzard HMM with cross-linked heads. When HMM molecules in this preparation were rotary-shadowed and observed in an electron microscope, many head pairs were in contact with each other. The amount of HMM with cross-linked heads determined by electron microscopy was equal to that of the cross-linked NH2-terminal 24K tryptic fragments of HMM heavy chains determined by NaDodSO4 gel electrophoresis, indicating that this cross-linking is primarily responsible for the contact observed between two HMM heads. Most pairs of the contacted heads originated in the same HMM molecule, although a few pairs belonged to different HMM molecules. Cross-linking between the two heads of the same HMM molecule appeared to occur within the distal, more globular half of each head. However, the cross-linking sites were located at different positions within the globular portion. The actin-activated Mg-ATPase activity of the HMM sample treated with EDC in the presence of actin increased in a biphasic manner, depending on the concentration of F-actin, with two apparent association constants: 2.9 x 10(4) M-1 and one much less than 1 x 10(4) M-1. Since the apparent association constant obtained with the HMM control was similar to the latter value, the association constant for HMM molecules with cross-linked heads was identified to be the former value. The binding of HMM to actin was thus strengthened at least by a factor of 3 by the cross-linking between two HMM heads. These results suggest that HMM heads are trapped by treatment with EDC in the rigor complex configuration and that this configuration is retained even after the HMM has been released from actin. The EDC reactivity of rabbit skeletal muscle HMM, however, was different from that of chicken gizzard HMM. The treatment of acto-HMM complexes with EDC did not generate cross-linking between two skeletal muscle HMM heads.

Actins↗
PubMed1990

[CT-guided biopsy of thoracic mass lesions followed by fast stain technique].

We performed CT-guided needle biopsy of 92 thoracic mass lesions using a Rotex-II screw needle. Fast stain technique was performed for an immediate evaluation of the specimen in the last 39 procedures. The overall accuracy of malignancy was 93.2%, and the correct histological typing was obtained in 82.8% of malignancy proven at surgery or autopsy. The method enabled histopathological diagnosis of thoracic lesions, which could not obtained by other diagnostic modalities including fiberoptic bronchoscopy or fluoroscopy-guided biopsy. The true positive rate increased up 10.2% to 91.3% by introducing fast stain technique. A close cooperation between radiologists and cytopathologists was essential for performing this CT-guided biopsy procedure followed by fast stain technique.

Adenocarcinoma↗
PubMed1990

Clonal variation of adenylyl cyclase activity in a rat tumor cell line caused by change in G protein-catalytic unit interaction.

Two subclones of the rat XC cell line characterized by different morphology exhibited quite different adenylyl cyclase responses upon various stimulations. Upon treatment with cholera toxin, clone RK1 accumulated a high level of intracellular cAMP thereby changing its polygonal morphology to an elongated morphology, while the other clone, LK1, with a fibroblastic morphology, failed to increase the intracellular cAMP and remained morphologically unchanged. When membrane fractions derived from these two clones were stimulated with 10 microM forskolin, 10 microM GTP gamma S, or 10 mM NaF, five- to 20-fold more cAMP was accumulated in RK1-derived membranes than in LK1-derived membranes. With the same membrane fractions, upon treatment with Mn(+)+, which directly stimulates the catalytic unit, a high level of cAMP was accumulated both in RK1 and LK1, indicating that the catalytic function inducible by Mn(+)+ was similar in both clones. There was no significant difference in the level of expression of G protein alpha 2, alpha i (at least alpha i1 and alpha i2), and beta subunits between LK1 and RK1. Cholate extracts of the membrane proteins of LK1 and RK1 reconstituted the adenylyl cyclase activity of the cyc- variant of S49 lymphoma cells to the same level. Therefore, it is inferred that the defect in LK1 resides in the interaction of stimulatory G proteins and the actual catalyst.

Adenosine Diphosphate Ribose↗
PubMed1990

Reproductive disorders in female SHR rats infected with sialodacryoadenitis virus.

Effects of sialodacryoadenitis virus infection on the reproduction of female SHR rats were studied. The oestrous cycle was considerably perturbed in most infected rats, the perturbation was observed initially between Days 0 to 10 post infection and the effect persisted for 6 to 18 days. About half of the foetuses of dams infected on Day 0 of gestation were found dead while only 4% of the foetuses from non-infected dams were found dead. Five or six days after infection on Day 0 of gestation, some infected dams were shown to have metritis, and virus antigen was detectable within the endometrium as well as exudate cells. In dams infected on Day 5 or later of gestation and severely diseased, the offspring showed a low survival rate possibly because of inadequate nursing.

Animals↗
PubMed1990

A highly sensitive enzyme-linked immunosorbent assay for etoposide using beta-D-galactosidase as a label.

A highly sensitive enzyme-linked immunosorbent assay (ELISA) for etoposide (EP) was developed, which is capable of accurately measuring as little as 40 pg EP/ml. Anti-EP sera were obtained by immunizing rabbits with EP conjugated with mercaptosuccinyl bovine serum albumin (MS.BSA) using N-[beta-(4-diazophenyl)ethyl]maleimide (DPEM) as a heterobifunctional coupling agent. An enzyme marker was similarly prepared by coupling EP with beta-D-galactosidase (beta-Gal; EC 3.2.23) via DPEM. This ELISA was specific for EP and showed a very slight cross-reactivity with its major metabolite, cis-hydroxy acid of EP (0.91%), but none with 4'-demethylepipodophyllotoxin and drugs commonly used with EP in combination chemotherapy for cancer treatment. The values for EP concentration detected by this assay were comparable with those detected by the high-performance liquid chromatography (HPLC) method. However, the ELISA was about 1,250 times more sensitive in detecting EP at lower concentrations. Using this assay, drug levels were easily determined in the blood and urine of rats for 7 h after i.v. administration of EP at a single dose of 3 mg/kg. Due to its sensitivity and specificity for EP, the ELISA should prove to be a valuable new tool for use in clinical pharmacological studies.

Animals↗
PubMed1990

Provocation of massive hepatic necrosis by endotoxin after partial hepatectomy in rats.

When rats received endotoxin 48 hours after two-thirds liver resection, 50% of them died within 12 hours with massive hepatic necrosis at a dose that did not affect sham-operated rats. In the hepatic sinusoids, fibrin deposition and endothelial cell destruction occurred 5 hours after endotoxin administration. When antithrombin III concentrate was infused concomitantly with endotoxin administration, all rats survived 12 hours, and the extent of hepatic necrosis and the deranged serum glutamic pyruvic transaminase values were significantly attenuated at 5 hours compared with those in the control rats. Similar improvements in the incidence of mortality and liver injury were observed after treatment with gum arabic before hepatectomy. The stimulatory state of Kupffer cells based on the ability to produce superoxide anions estimated by formazan deposition after liver perfusion with nitro blue tetrazolium and phorbol myristate acetate was increased between 24 and 72 hours after operation. This increase disappeared after gum arabic treatment. It is concluded that massive hepatic necrosis can occur as a result of sinusoidal fibrin deposition provoked by endotoxin in partially hepatectomized rats. Activated Kupffer cells may contribute to this provocation.

Animals↗