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Biomedical subjects

H Fujioka

Publications and source records attributed to H Fujioka.

At least 253 records · Page 14Linked to original sources
PubMed1991

Enhancement of post-hypoxic contractile and metabolic recovery of perfused rat hearts by dl-propranolol: possible involvement of non-beta-receptor mediated activity.

The present study was undertaken to elucidate a possible role of non-beta-receptor mediated effects in dl-propranolol-induced enhancement of post-hypoxic contractile and metabolic recovery in perfused rat hearts. The rat hearts were perfused for 30 min under reoxygenated conditions following 15 min-substrate free-hypoxic perfusion, and the cardiac performance and myocardial metabolism were examined. Hypoxia induced complete cessation of cardiac contractile force, depletion of myocardial high-energy phosphates, release of ATP metabolites and creatine kinase from the heart. Subsequent reoxygenation produced little recovery of cardiac contractile activity and tissue high-energy phosphates, further enhancement of the release of creatine kinase and the accumulation of tissue calcium. Treatment of the hypoxic hearts with dl-propranolol, d-propranolol and atenolol was performed during 5 to 15 min of hypoxic perfusion. dl-Propranolol and d-propranolol at the concentration of 45 microM elicited a significant recovery of cardiac contractile activity and restoration of myocardial high-energy phosphates. This treatment also resulted in a suppression of the release of creatine kinase and ATP metabolites and the tissue calcium accumulation observed during hypoxia and/or reoxygenation. However, such beneficial effects were not seen in hearts treated with 45 microM atenolol. dl-Propranolol and atenolol, but not d-propranolol, in a concentration of 45 microM have been shown to reveal beta-adrenoceptor blocking action. Thus, the results suggest the involvement of non-beta-receptor mediated effects of propranolol in the enhanced post-hypoxic contractile and metabolic recovery of the perfused rat heart. The non-beta-receptor mediated activity of these drugs appears to be related to their ability to suppress the maximal driving frequency of left atrial preparations.

Animals↗
PubMed1991

Observation of spinal canal and cisternae with the newly developed small-diameter, flexible fiberscopes.

Small-diameter (0.5-, 0.9-, and 1.4-mm) flexible fiberscopes were developed for visual diagnosis of spinal canal diseases. The fiberscopes were introduced via a Tuohy needle into the subarachnoid and epidural spaces of ten patients with various pain syndromes. Clear visualization of the subarachnoid space was achieved using the fiberscopes. The epidural space could be visualized only during withdrawal of the fiberscope. In five cases, the fiberscope could be advanced up to the level of the cisternae without causing the patient any discomfort. A slight headache and transient fever were noted after the examination in five and two cases, respectively, but no other complications occurred. Interestingly, preexisting pain diminished (two cases) or disappeared (one case) after the myeloscopy in three of five cases in which the myeloscopy revealed aseptic adhesive arachnoiditis. Further studies should be carried out to evaluate the usefulness of this technique.

Adult↗
PubMed1991

Inhibition of the action of a stimulatory GDP/GTP exchange protein for smg p21 by acidic membrane phospholipids.

A stimulatory GDP/GTP exchange protein for smg p21 (smg p21 GDS) stimulated the dissociation of GDP from smg p21B. This reaction was inhibited by acidic membrane phospholipids such as phosphatidylinositol, phosphatidylinositol-4-monophosphate, phosphatidylinositol-4,5-bisphosphate, phosphatidic acid, and phosphatidylserine but not by phosphatidylcholine or phosphatidylethanolamine. These acidic phospholipids inhibited the smg p21 GDS action in a manner competitive with both smg p21 GDS and smg p21B. smg p21 GDS has other actions to inhibit the binding of smg p21B to membranes and to induce the dissociation of prebound smg p21B from the membranes. The acidic phospholipids also inhibited these two actions of smg p21 GDS. smg p21B has a polybasic region and an isoprenoid moiety in its C-terminal region which are necessary for its membrane-binding activity and its sensitivity to the smg p21 GDS actions. Therefore, it is possible that acidic membrane phospholipids interact with this polybasic region and thereby inhibit the smg p21 GDS actions.

Animals↗
PubMed1991

In vitro activities of acridone alkaloids against Pneumocystis carinii.

Acridone alkaloids isolated from plants of the family Rutaceae have antiplasmodial activity in rodent models of malaria. Because a variety of antimalarial agents have also been shown to have activity against Pneumocystis carinii, we tested six of these alkaloids in an established culture model for P. carinii. Atalaphillinine and glycobismine A inhibited growth of cultured P. carinii at concentrations of 2.7 and 1.7 microM, respectively. This potency of effect is similar to that of chloroquine (3 microM) but somewhat less than that of primaquine (0.4 microM), which was previously evaluated in the same system.

Acridines↗
PubMed1991

Molecular cloning of the cDNA for stimulatory GDP/GTP exchange protein for smg p21s (ras p21-like small GTP-binding proteins) and characterization of stimulatory GDP/GTP exchange protein.

We have recently purified to near homogeneity the stimulatory GDP/GTP exchange protein for smg p21s (ras p21-like GTP-binding proteins) from bovine brain cytosol. This regulatory protein, named GDP dissociation stimulator (GDS), stimulates the GDP/GTP exchange reaction of smg p21s by stimulating the dissociation of GDP from and the subsequent binding of GTP to them. In this study, we have isolated and sequenced the cDNA of smg p21 GDS from a bovine brain cDNA library by using an oligonucleotide probe designed from the partial amino acid sequence of the purified smg p21 GDS. The cDNA has an open reading frame encoding a protein of 558 amino acids with a calculated Mr value of 61,066, similar to the Mr of 53,000 estimated for the purified smg p21 GDS by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and sucrose density gradient ultracentrifugation. The isolated cDNA is expressed in Escherichia coli, and the encoded protein exhibits smg p21 GDS activity. smg p21 GDS is overall hydrophilic, but there are several short hydrophobic regions. The smg p21 GDS mRNA is present in bovine brain and various rat tissues. smg p21 GDS has low amino acid sequence homology with the yeast CDC25 and SCD25 proteins, which may regulate the GDP/GTP exchange reaction of the yeast RAS2 protein, but not with ras p21 GTPase-activating protein, the inhibitory GDP/GTP exchange proteins (GDP dissociation inhibitor) for smg p25A and rho p21s, and the beta gamma subunits of heterotrimeric GTP-binding proteins such as Gs and Gi.

Amino Acid Sequence↗
PubMed1991

[A case of diphenylhydantoin-induced pneumonitis].

A 60-year-old man had been administered diphenylhydantoin (DPH) for prevention of convulsive seizures following clipping of an aneurysm of the middle cerebral artery. About one month after the commencement of DPH administration, he developed cough and low grade fever. He was treated with various antibiotics, but his condition increasingly worsened. Chest X-ray film revealed bilateral interstitial processes throughout the entire lung fields. Transbronchial lung biopsy was performed and the obtained specimen showed histological findings compatible with drug-induced pneumonitis. Administration of DPH was stopped immediately and 50 mg/day of prednisolone was started. The patient's condition rapidly improved, and the abnormal shadows on chest X-ray film gradually diminished. The lymphocyte stimulation test by DPH was positive with a stimulation index of 282%.

Humans↗
PubMed1991

Post-translational modifications of the C-terminal region of the rho protein are important for its interaction with membranes and the stimulatory and inhibitory GDP/GTP exchange proteins.

We have recently found, by use of the rhoA p21 purified from bovine aortic smooth muscle, that it is similarly post-translationally processed as described for ras p21s: it is first geranylgeranylated at the cysteine residue in the C-terminal region followed by removal of the three C-terminal amino acids and the subsequent carboxyl methylation of the revealed C-terminal cysteine residue. In the present study, we investigated the function(s) of these post-translational modifications of the C-terminal region of rhoA p21 by use of the rhoA p21s purified from bovine aortic smooth muscle and rhoA p21-overexpressing Escherichia coli since the bacterial protein was not modified with a geranylgeranyl moiety. Bovine rhoA p21 bound to plasma membranes and phosphatidylserine-linked Affigel, but bacterial rhoA p21 did not bind to them. The inhibitory GDP/GTP exchange protein for rhoA p21, named GDP dissociation inhibitor (GDI), made a complex with the GDP-bound form of bovine rhoA p21 and thereby inhibited the dissociation of GDP from and the subsequent binding of GTP to it. However, rho GDI neither made a complex with the GDP-bound form of bacterial rhoA p21 nor affected these reactions of the bacterial protein. The stimulatory GDP/GTP exchange protein for rhoA p21, named GDP dissociation stimulator (GDS), stimulated the dissociation of GDP from bovine rhoA p21, but was inactive for the bacterial protein. In contrast, the GTPase activating protein for rhoA p21 is active not only for bovine rhoA p21 but also for the bacterial protein. These results suggest that the post-translational modifications of the C-terminal region of bovine rhoA p21, most presumably the geranylgeranylation, which are absent in bacterial rhoA p21, play important roles in its interaction with membranes and the stimulatory and inhibitory GDP/GTP exchange proteins but not with the GAP.

Animals↗
PubMed1990

Comparison of the mode of action of ras p21 with those of protein kinases A and C in the stimulation of gene expression in NIH/3T3 cells.

To compare the mode of action of ras p21 with those of protein kinases A and C in the regulation of gene expression in NIH/3T3 cells, we investigated the transcriptional activity of various enhancer/promoters and enhancer motifs in the cells transfected with the c-Ha-rasva112 complementary DNA (cDNA). The results indicate that the c-Ha-rasva112 protein stimulates the enhancer/promoters of the c-fos gene, the metallothionein IIA gene, the simian virus 40 (SV40) virus genome and the Rous sarcoma (RS) virus genome, and the serum-response element and the 12-O-tetradecanoylphorbol-13-acetate (TPA)-response element in a manner independent of protein kinases A and C in NIH/3T3 cells.

Animals↗
PubMed1990

A small GTP-binding protein (G protein) recognized by smg p25A GDP dissociation inhibitor (GDI) in human platelet membranes and GDI for this small G protein in human platelet cytosol.

We have recently purified from bovine brain cytosol a novel type of regulatory protein for smg p25A, named smg p25A GDP dissociation inhibitor (GDI), that regulates the GDP/GTP exchange reaction of smg p25A by inhibiting the dissociation of GDP from and thereby the subsequent binding of GTP to it. This smg p25A GDI is inactive for other ras p21/ras p21-like small GTP-binding proteins (G proteins) including c-Ha-ras p21, smg p21, rhoA p21 and rhoB p20. In human platelet membranes, smg p25A was not detected but a G protein with an apparent Mr value of 24,000 (24KG) was recognized by smg p25A GDI and the dissociation of GDP from and the binding of GTP to 24KG were inhibited by smg p25A GDI. The doses of smg p25A GDI necessary for these activities for both 24KG and smg p25A were the same. This 24KG was not recognized by an anti-smg p25A monoclonal antibody. The GDI activity for human platelet 24KG and smg p25A was detected in human platelet cytosol. This human platelet GDI was recognized by an anti-smg p25A GDI polyclonal antibody. These results indicate that there is a 24KG-24KG GDI system similar to a smg p25A-smg p25A GDI system in human platelets.

Animals↗
PubMed1990

Heterotopic pancreas: a rare cause of bile duct dilatation--report of a case and review of the literature.

A case of a 77 year old woman with a heterotopic pancreas in the distal common bile duct is reported herein. The patient had no symptoms, but an ultrasound examination showed bile duct dilatation and subsequent endoscopic retrograde cholangiography demonstrated a spherical filling defect in the distal common bile duct. Under suspicion of a benign neoplasm in the common bile duct, resection of the common bile duct and hepaticojejunostomy using a Roux-en Y jejunal limb were successfully performed. Pathological examination revealed heterotopic pancreatic tissue in the distal common bile duct. This is only the ninth reported case of heterotopic pancreas occurring in the common bile duct or ampulla of Vater, and thus, a review of the literature is also given.

Aged↗
PubMed1990

Monoclonal antibody to pseudouridine used to develop a radioimmunoassay.

Pseudouridine, a component of tRNA, was modified to yield the derivatives: succinyl, palmitoyl pseudouridine, and protein conjugates. These derivatives were used in preparation of monoclonal antibodies specifically directed to pseudouridine. MAbs from three hybridomas (OAL 881, 812 and 814) were established and shown to be directed to pseudouridine, uridine and uracil. OAL 881 was equally reactive with the three substrates, OAL 812 showed the same reactivity for pseudouridine and uracil, while OAL 814 showed a reactivity mainly for pseudouridine. MAb OAL 814 was used in a radioimmunoassay (RIA) system unique for pseudouridine. A good dose-response curve was observed in the range between 31.3 and 2000 nmol/ml. Intra- and inter-assay CV values were below 4.1% and 7.4% respectively, and good results were obtained from recovery of added material and dilution tests. The ratio of pseudouridine/creatinin in urine was significantly higher in patients with cancer than in normal subjects.

Antibodies, Monoclonal↗
PubMed1990

Improvement of semen characteristics after surgical repair of bilateral testicular varicocele as compared to unilateral varicocele patients.

The operative treatment for surgical repair of bilateral testicular varicoceles was evaluated in terms of the improvement achieved in the sperm density and percentage progressive motile sperm. These parameters were compared for 27 cases of bilateral varicocele diagnosed by palpation and subjected to bilateral high ligation of the internal spermatic vein and for 40 cases of left unilateral testicular varicocele. There were no significant differences in preoperative values (such as sperm density; progressive motile sperm; serum levels of luteinizing hormone, follicle-stimulating hormone, and testosterone; and Johnson's score count) between the bilateral and unilateral testicular varicocele groups. The improvement in postoperative sperm density in the cases with bilateral testicular varicocele was apparently less satisfactory than in the cases with testicular varicocele only on the left side.

Adult↗
PubMed1990

Testicular macromolecular synthesis in men with varicocele.

The synthesis of DNA, RNA, and protein by varicocele testes with spermatogenic dysfunction was studied by examination of the levels of incorporation of [3H]thymidine, [14C]uridine, and [14C]leucine into the testicular tissue at 31 degrees C in vitro. The results suggest that DNA synthesis by the testis with moderate tubular damage is impaired whereas synthesis of RNA and protein is not. The cell regenerative ability of the testis with moderate tubular damage may be poor in spite of the preservation of testicular cell RNA and protein synthesis.

Adult↗
PubMed1990

Testicular steroids in spermatic and peripheral veins after single injection of hCG in patients with varicocele.

To determine the function of Leydig cells in patients with varicocele, hCG-stimulated levels of progesterone (Prog), 17 alpha-Hydroxy-4-pregnene-3,20-dione (17OHP), 4-Androstene-3,17-dione (A-dione), testosterone (T), and estradiol-17 beta (E2) in both spermatic and peripheral veins were measured. Seventy-two patients with idiopathic varicocele were divided into four groups: patients in group 1 were untreated, whereas patients in groups 2, 3, and 4 were given a single i.m. injection of 10,000 IU hCG 24 h, 96 h, and 168 h before surgery, respectively. In the spermatic and peripheral veins, levels of Prog, 17OHP, and E2 showed peaks at 24 h, whereas levels of A-dione and T showed peaks at 96 h. Significant increases in the ratios of spermatic veins 17OHP to A-dione and 17OHP to T, and a significant decrease in the ratio of T to E2, was found 24 h following hCG treatment. These results demonstrate that, following hCG injection, there is a transient inhibition of testicular C17-20-lyase activity, probably mediated by E2, even in subfertile males with varicocele.

Adult↗
PubMed1990

Activities of new acridone alkaloid derivatives against Plasmodium yoelii in vitro.

Forty-seven new acridone alkaloid derivatives (SA compounds) were tested for antimalarial activity in vitro. At a concentration of 1.0 microgram/ml, six of these inhibited 50% or more of the incorporation of [3H]hypoxanthine into Plasmodium yoelii in vitro. The four most potent compounds, SA 3757, SA 3548, SA 3761 and SA 3499, showed 50% inhibitory concentration (IC50) values of 0.023 microgram/ml, 0.03 microgram/ml, 0.053 microgram/ml and 0.15 microgram/ml, respectively. The chemotherapeutic indexes of these four acridones, based on the ratio of the 50% lethal concentration (LC50) values for cell growth of L1210 cells to the IC50 for inhibition of uptake of [3H]hypoxanthine into P. yoelii, were calculated to be equal to or more higher (greater than 870, 263, 189 and greater than 133, respectively) than chloroquine diphosphate (315) or pyrimethamine (87).

Acridines↗
PubMed1990

Molecular cloning and characterization of a novel type of regulatory protein (GDI) for the rho proteins, ras p21-like small GTP-binding proteins.

We have recently purified to near homogeneity a novel type of regulatory protein for the rho proteins, ras p21-like small GTP-binding proteins, from bovine brain cytosol. This regulatory protein, named GDP dissociation inhibitor for the rho proteins (rho GDI), regulates the GDP/GTP exchange reaction of the rho proteins by inhibiting the dissociation of GDP from them, and the subsequent binding of GTP to them. In the present studies, we have isolated the cDNA of rho GDI from a bovine brain cDNA library using oligonucleotide probes designed from the partial amino acid sequences of the purified rho GDI and determined its complete nucleotide and deduced amino acid sequences. The cDNA contains an open reading frame encoding a protein of 204 amino acids with a calculated Mr value of 23,421. This Mr value is similar to those of the purified rho GDI estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and sucrose density gradient ultra-centrifugation, both of which are about 27,000. The rho GDI cDNA is expressed in Escherichia coli and COS7 cells and the encoded protein exhibits rho GDI activity. The 1.9-kilobase rho GDI mRNA corresponding to the isolated cDNA is detected in various rat tissues by Northern blot analysis. Hydropathy analysis indicates that rho GDI is overall hydrophilic except for one hydrophobic region. Computer homology search has revealed that rho GDI is a novel protein that does not share a high amino acid sequence homology with any known protein.

Amino Acid Sequence↗
PubMed1990

[A case report of high plasma renin activity in chronic pulmonary disease and the effect of angiotensin-II-analogue (1-sarcosine, 8-isoleucine-angiotensin-II)].

Five patients with chronic pulmonary diseases (3 pulmonary emphysema, 1 chronic respiratory failure caused by old tuberculosis, 1 diffuse panbronchiolitis) showed a marked increase of plasma angiotensin-I and PRA level, which was accompanied by an increase of angiotensin-II level, however, whose systemic blood pressure was not elevated. The intravenous infusion of angiotensin-II-analogue (1-Sarcosine, 8-Isoleucine-Angiotensin-II) elicited an antagonistic blood pressure response resembling Bartter's syndrome.

1-Sarcosine-8-Isoleucine Angiotensin II↗