Differential effects of Na+, K(+)-ATPase inhibition by ouabain on acid secretory responses to histamine and bethanechol in the mouse isolated stomach

1. The effect of Na+,K(+)-ATPase inhibition by ouabain on gastric acid secretion was studied in the mouse isolated whole stomach preparation. 2. Ouabain caused a transient enhancement of histamine-induced gastric acid secretion followed by an inhibitory phase. On the other hand, ouabain caused a rapid reduction of bethanechol-stimulated acid secretion without an enhancement phase. 3. In dibutyryl cyclic AMP-induced acid secretion, ouabain led to a transient increase in acid secretion followed by a fall, as was seen with the histamine stimulation. Ouabain caused a rapid reduction of A23187-induced acid secretion. 4. Ouabain by itself increased basal acid secretion, and thereafter slowly suppressed the acid secretion. 5. Atropine inhibited both the ouabain-induced enhancement of the stimulated gastric acid secretion and the ouabain-induced stimulation of basal acid secretion. 6. The present study showed that Na+,K(+)-ATPase inhibition by ouabain caused a phasic enhancement of the stimulated gastric acid secretion through release of endogenous acetylcholine when the secretagogues act via an intracellular cyclic AMP pathway. It also inhibited the stimulated acid secretion irrespective of secretagogues, probably through its inhibitory effect on Na+,K(+)-ATPase in the gastric parietal cell.

In vitro antibacterial activity of FK037, a new parenteral broad-spectrum cephalosporin, against recent clinical isolates in the fields of obstetrics and gynecology

The antibacterial activity of a new parenteral cephalosporin, FK037 was assessed against recent aerobic and anaerobic strains isolated from patients in the fields of obstetrics and gynecology during the period between January 1992 and June 1993. The MICs of FK037 for 90% of the clinical isolates tested were 0.10 microgram/ml for Escherichia coli and Klebsiella pneumoniae, 0.20 microgram/ml for Streptococcus agalactiae, 0.39 microgram/ml for Gardnerella vaginalis, 0.78 microgram/ml for Staphylococcus epidermidis, Peptostreptococcus anaerobius and Mobiluncus spp., 1.56 micrograms/ml for Peptostreptococcus magnus, 3.13 micrograms/ml for methicillin-sensitive Staphylococcus aureus, 25 micrograms/ml for methicillin-resistant S. aureus (MRSA), Bacteroides fragilis and Prevotella disiens, 100 micrograms/ml for Bacteroides thetaiotaomicron and Prevotella bivia; and > 100 micrograms/ml for Enterococcus faecalis. FK037 was superior in potency to ceftazidime against all strains except E. faecalis, P. anaerobius and P. bivia. It was 4- to 16-fold more active than cefotaxime against aerobic gram-positive bacteria and P. disiens, and its activity was similar to that of cefotaxime against the other strains. FK037 had 4- to 16-fold stronger activity than flomoxef against MRSA, S. agalactiae and E. coli and a similar activity to flomoxef against the other strains except G. vaginalis and B. fragilis that were 4-fold more sensitive to flomoxef than to FK037.

[Role of clinical laboratory physicians in clinical hematology]

The specialty for laboratory hematology has been difficult to define in Japan, since both the clinical laboratory physician and clinical hematologist usually engage in this field. I propose herein that the specialty for laboratory hematology belongs to laboratory medicine. This makes it possible for the clinical laboratory physician to provide active medical assistance for laboratory diagnosis of hematological disorders so that the clinical hematologist can effectively perform practical management of the patient. For this purpose, I describe the program of postgraduate education for doctors in laboratory hematology. General instructional objectives (GIOs) and specific behavioral objectives (SBOs) are proposed to set the education program for clinical laboratory physicians and to establish the specialty of laboratory hematology in Japan. For the establishment of this system, the committee for the Japanese educational program for the medical board should authorize this newly developed conception for the clinical laboratory physicians who work in the hematology laboratory.

Computed tomography of an intracranial lipoma confined in the suprasellar cistern

A case of large intracranial lipoma involving the suprasellar cistern is presented in a 50-yr-old man with a history of occipital headaches. Evaluations by routine computed tomography (CT) combined with metrizamide CT cisternography were extremely useful in the diagnosis of this rare condition. Intracranial lipomas are reviewed in the literature and the role of CT evaluations is discussed.

Efficient expression of E. coli dihydrofolate reductase gene by an in vitro translation system using phosphorothioate mRNA

Dihydrofolate reductase (DHFR) of Escherichia coli (E. coli) was synthesized in a cell-free translation system of E. coli directed by phosphorothioate-containing mRNA (thio-mRNA) which was polymerized by an in vitro transcription of the DHFR gene in the presence of SP diastereomers of ribonucleoside 5'-O-(1-thiotriphosphates). The molecular weights of the products thus obtained were identical to those with the unsubstituted mRNA. Furthermore, the thio-mRNA for DHFR showed higher translational activities than the corresponding unsubstituted mRNA. It is suggested that this effectiveness resulted from the higher stability of thio-mRNA in the cell-free translation system. Amongst the various types of thio-mRNAs, the single substitution of adenosine residues was most effective in translational activity. This higher translational activity of thio-mRNA compared with the unsubstituted mRNA was also demonstrated in a continuous flow cell-free system originally developed by Spirin et al. (1988). Therefore, introduction of sulfur atoms into phosphodiester bonds of mRNA appears to be a useful strategy for the stabilization of mRNA in large-scale protein production in vitro.

Scaphoid fracture as a "puncher's fracture"

We investigated 18 scaphoid fractures induced by punching. The wrist position while punching was neutral to slight palmar flexion. We postulated that the mechanism of the fracture was caused by the concentration of the external force to the second metacarpus. The forces are then dispersed to the trapezium and trapezoid, which produces shear stress at the waist of the scaphoid. In spite of the differences in mechanism, the location of the fracture was similar to fractured scaphoids caused by wrist extension injuries. Regardless of the wrist positions, the carpal scaphoid is most vulnerable to fracture due to its characteristic morphology.

Molecular cloning of brevican, a novel brain proteoglycan of the aggrecan/versican family

To clone novel brain proteoglycans, we employed a strategy based on polyclonal antisera that recognize multiple proteoglycan core proteins. By using an antiserum raised against a fraction enriched for proteoglycans, we isolated three groups of cDNAs from a bovine brain lambda gt11 library. One of the cDNA groups has been fully sequenced and shown to encode a novel proteoglycan core protein of the aggrecan/versican family. This proteoglycan, named brevican, carries chondroitin sulfate chains, and, like other members of the family, contains a hyaluronic acid-binding domain in its N-terminal region, an epidermal growth factor-like repeat, a lectin-like and a complement regulatory protein-like domains in its C-terminal region. In contrast, the central region of brevican is much shorter than that of aggrecan, versican, or neurocan, and shows little homology with these proteoglycans. Brevican core protein exists as a 145 kDa full-length form and a 80 kDa N terminally truncated form. A significant amount of brevican devoid of any glycosaminoglycan chains is present in the brain, indicating that brevican is a "part-time" proteoglycan. Northern blot analysis reveals that a single 3.3-kilobase brevican transcript is present predominantly in the brain, and that it is expressed in primary cerebellar astrocytes but not in neurons.

[Changes in urine oxygen tension (PuO2) during anesthesia with isoflurane and sevoflurane]

Leonhardt and coworkers have suggested that PuO2 may indicate degree of renal medullary perfusion and function. The changes in PuO2 during N2O-O2-isoflurane anesthesia (GOI) and N2O-O2-sevoflurane anesthesia (GOS) were studied in 20 patients (GOI group: 10 cases, GOS group: 10 cases) who underwent elective surgeries. In the GOI group, PuO2 decreased significantly 30 and 60 minutes after the beginning of surgical incision, and it returned to the previous value immediately after the cessation of isoflurane. In the GOS group PuO2 decreased starting 30 minutes after the beginning of surgical incision until 10 minutes after the cessation of sevoflurane. These results suggest that isoflurane and sevoflurane administration caused a reduction in renal medullary perfusion, and that the low perfusion during sevoflurane anesthesia lasted longer than during isoflurane anesthesia. Measurement of PuO2 has a number of problems, but we believe that PuO2 is useful as an indicator of renal medullary blood flow.

Identification of bovine serum transferrin phenotypes by polyacrylamide gel isoelectric focusing (PAGIEF)

Each of four common homozygous bovine serum transferrins Tf A, Tf D1, Tf D2, and Tf E gave only two main bands in polyacrylamide gel isoelectric focusing (PAGIEF). This is considered to be due to the co-migration of the main components 2a and 3a with the main components 2b and 3b, respectively, in PAGIEF. Ten phenotypes, which are controlled by four alleles TfA, TfD1, TfD2, and TfE, were distinguishable from each other in PAGIEF.

Endogenous synthesis of N-methylnorsalsolinol in rat brain during in vivo microdialysis with epinine

The in vivo metabolic pathway for the synthesis of N-methylnorsalsolinol, an analogue of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), was studied in the rat brain. N-Methyldopamine (epinine) was perfused at the striatum of the rat brain by in vivo microdialysis. N-Methylnorsalsolinol (NMNSAL) was identified in the brain dialysate after epinine perfusion using gas chromatography-selected-ion monitoring mass spectrometry (GC-SIM-MS). We demonstrated that NMNSAL could be synthesized from epinine with an aldehyde by the Piclet-Spengler condensation reaction in the rat brain.

Serial changes in coagulant activities after thrombolytic therapy for acute myocardial infarction

Early reocclusion and bleeding complications are still unresolved problems in thrombolytic therapy for acute myocardial infarction (AMI). In the present study, 16 patients treated with either fibrin-specific tissue-type plasminogen activator (t-PA) or nonspecific urokinase (UK) were studied to determine the effects of thrombolytic therapy on serial hemostatic states. Hemostatic states of each patient were estimated by measuring various plasma markers at one- to two-hour intervals during the first six hours of therapy, daily during the next three days, and subsequently on day 7. Two markers of plasma thrombin generation, thrombin antithrombin III complex (TAT) and prothrombin fragment 1 + 2 (F 1 + 2), showed an activated coagulant state immediately after thrombolytic therapy. The amount of thrombin generation indicated by these markers showed significant positive correlation with direct markers of fibrinolysis such as fibrin degradation products (FDP), while it did not show any correlation with the markers for plasmin generation. The potential for coagulation as indicated by prothrombin time (%) decreased with thrombolysis using fibrin nonselective agents, owing perhaps to destruction of coagulant factors by free plasmin. Fibrinolytic activity induced by thrombolytic therapy for AMI caused transient activation of the coagulant system, which could contribute to early reocclusion. Fibrin nonselective agents decreased the potential for coagulation by destroying clotting factor through the generation of free plasmin. These data provide theoretical support for simultaneous administration of anticoagulant therapy with fibrin-specific thrombolytic agents.

The potent depressant effects of N3-phenacyluridine in mice

The hypnotic activity of N3-phenacyluridine in 2.0 mumol/mouse by intracerebroventricular (i.c.v.) injection was 20 times stronger than that of known N3-benzyluridine. In 0.5 mumol/mouse, i.c.v., this compound strongly potentiated both pentobarbital- and diazepam-induced sleep as compared to N3-substituted uridines, including N3-benzyluridine. Furthermore, the compound caused motor incoordination as well as decreasing spontaneous activity in the same dose. These results indicate that among the N3-substituted uridines and related compounds previously reported, N3-phenacyluridine possesses potent depressant effects.

Template-dependent peptide formation on ribosomes catalyzed by pyridine

We found that poly(U)-dependent polyphenylalanine synthesis on Escherichia coli ribosomes was extremely accelerated in the presence of a high concentration of pyridine. In this reaction, chemical energy sources, such as ATP and GTP, and soluble protein factors are not required, but the template and ribosomes are essential for the progress of the reaction. The reaction was inhibited by the antibiotics which inhibit the usual bacterial translation process on the ribosomes. These observations clearly demonstrate that the pyridine-catalyzed amino acid condensation reaction proceeds on the ribosome.

Myelodysplastic syndrome associated with immunoblastic lymphadenopathy-like T-cell lymphoma: simultaneous clinical improvement with chemotherapy

A 75-year-old woman presented with anemia, lymphadenopathy, hepatomegaly and lingual tumor, but no constitutional symptoms. The laboratory data showed pancytopenia and polyclonal hypergammaglobulinemia. A bone marrow aspirate represented an apparent myelodysplastic syndrome (MDS) feature, specifically, refractory anemia with excess of blasts. A lymph-node biopsy revealed the disappearance of normal architecture, small arborizing blood vessels, large lymphoid cells with prominent cytoplasm (so-called pale cells) and a clonal proliferation of T-lymphocytes. The patient was diagnosed as having MDS associated with immunoblastic lymphadenopathy (IBL)-like T-cell lymphoma. She was subsequently treated with cyclophosphamide, adriamycin, vincristine and prednisolone for lymphoma which successfully induced a remission of not only the T-cell lymphoma but also the MDS. The case suggested that MDS might be a paraneoplastic complication of IBL-like T-cell lymphoma.

Effects of chemical modification of arginine residues outside the active site cleft of ricin A-chain on its RNA N-glycosidase activity for ribosomes

Ricin A-chain, a protein that inactivates ribosomes by a specific RNA N-glycosidase activity, has been shown to be inactivated by chemical modification of a few arginine residues. When two or fewer arginine residues in the A-chain were modified with [14C]phenylglyoxal, arginines at positions of 193, 196, 213, and 234/235 were found to be modified, from amino acid compositions and radioactivities of the modified peptides that were obtained by cyanogen bromide cleavage followed by tryptic and chymotryptic digestion. All these arginines have side chains outside the active site cleft; the side chain of Arg213 is adjacent to the edge of the cleft, while other modified arginines are located on the opposite side of the cleft. Kinetic analysis showed that the modification of two arginine residues caused a 8-fold loss in kcat with a 3-fold increase in Km, suggesting that this modification mainly decrease the rate of depurination with an additional effect on the affinity for ribosomes. Neither the environment of tryptophan 211 at the bottom of the cleft nor an interaction of adenine with the cleft was changed by this modification, as judged by fluorescence spectroscopy, suggesting that a conformational change of the catalytic site does not occur upon the modification. These results, taken together with other works, suggest that some of the above arginine residues outside the active site cleft may additively contribute to the catalysis of depurination and/or the initial formation of the A-chain/ribosome complex.

The effect of bunazosin on monocrotaline-induced pulmonary hypertension in rats

In order to estimate the long-term hemodynamic and histologic effects of bunazosin hydrochloride on primary pulmonary hypertension (PPH), for which effective internal therapy has not yet been proposed, we produced subacute pulmonary hypertension in 6 week old Sprague-Dawley rats by injecting one dose of monocrotaline. Bunazosin (10 mg/kg) was administered intraperitoneally every day and bodyweight and hemodynamic parameters were measured. Right ventricle (RV) and left ventricle with septum (LV +S) were weight separately. Medial thickness of the small pulmonary artery was calculated. In the bunazosin group, the increase of right ventricular systolic pressure (RVSP) as pulmonary arterial systolic pressure and the ratio of RVSP to pulmonary flow were limited, without causing systemic hypotension, compared to the control group. Weight ratio of RV/(LV +S) had a tendency to be limited in the bunazosin group. As for medial thickness, there was no significant difference between the two groups. It may be concluded that bunazosin hydrochloride should be considered for clinical trials in treatment of PPH in humans.

A study of the complications induced by conventional and disposable contact lenses

We reviewed the charts of 23,068 patients (45,580 eyes) who were prescribed contact lenses in order to investigate the incidence of corneal complications in Japan. This population of patients included wearers of various types of conventional contact lenses as well as disposable extended wear lenses and daily disposable lenses. The rate of corneal complications and 95% confidence interval for each lens group were: polymethylmethacrylate (PMMA) lenses, 15.8% (358 of 2,267 eyes, 14.3-17.3%); rigid gas permeable lenses, 10.5% (3,191 of 30,459 eyes, 10.2-10.8%); acrylelastomer lenses, 7.2% (nine of 124 eyes, 2.7-11.7%); HEMA lenses 8.5% (534 of 6,261 eyes, 7.8-9.2%); high water content lenses, 4.0% (103 of 2,591 eyes, 3.6-4.4%); weekly disposable lenses, 4.9% (146 of 2,985 eyes, 4.1-5.7%); and daily disposable lenses, 2.5% (22 of 893 eyes, 1.5-3.5%). PMMA lenses had a significantly higher rate of corneal complications compared with other lenses, whereas the daily disposable lens had a significantly lower rate for the same. The majority of corneal complications for all types of lenses consisted of superficial punctate keratopathy, and there were no cases of corneal ulcers.

Recombinant rat nucleoside diphosphate kinase isoforms (alpha and beta): purification, properties and application to immunological detection of native isoforms in rat tissues

We previously demonstrated that at least two isoforms of nucleoside diphosphate (NDP) kinase, the products of two different tandemly arrayed genes, are present in rat. To understand the physiological role of each isoform, some biochemical properties of recombinant rat NDP kinase alpha- and beta-isoforms, produced in large amount, were studied. cDNAs of the two isoforms were inserted in an expression vector pET3b and recombinant enzymes were overproduced in Escherichia coli. Their primary structures were different from the native enzymes in that the latter suffer from modification of the NH2-terminal end. The two recombinant isoforms were purified from the cell lysate to apparent homogeneity by ammonium sulfate fractionation followed by three successive column chromatographies. Despite their extreme similarity in the amino-acid sequences, the two showed somewhat different enzymic properties in terms of di- and triphosphate nucleotide substrate specificity. They showed similar mobilities on SDS-PAGE as expected from their calculated molecular weight (alpha-isoform, 17,283 versus beta-isoform, 17,192) but differed in isoelectric point (alpha-isoform, pI 6.7; beta-isoform, pI 7.8) and heat stability. Polyclonal antibody which reacted with both isoforms and alpha-isoform-specific monoclonal antibodies differentially recognized native enzymes from rat tissues after the tissue extracts were separated by isoelectric focusing gel electrophoresis under a denaturation condition. The results showed that the alpha-isoform, though its amount varied from one tissue to another, was the major form in rat tissues examined compared with the beta-isoform which was detectable in brain and testis. There was no preference in their subcellular localization when examined with myelin, synaptosomal supernatant and total homogenate fractions from the rat cerebrum and cerebellum.

Functional and structural role of a tryptophan generally observed in protein-carbohydrate interaction. TRP-62 of hen egg white lysozyme

In order to elucidate the role of the aromatic ring in recognition of the sugar ring, Trp-62 of hen egg white lysozyme, which is proposed on the basis of x-ray crystallography data to make contact with a sugar ring through van der Waals interaction, was replaced with aliphatic amino acids (Leu, Ile, Val, and Ala) and Gly by site-directed mutagenesis. In spite of the loss of the aromatic effect, these mutant lysozymes, except for the Trp-62-->Gly mutant, showed higher bacteriolytic activity than the wild-type lysozyme. Furthermore, the Trp-62-->Gly mutant still retained appreciable bacteriolytic activity. On the other hand, by these replacements, the enzymatic activities toward non-charged substrates were markedly reduced. Additionally, the side-chain structure of position 62 was found to be largely responsible for recognition of a saccharide ring in its active site cleft. NMR analysis of the Trp-62-->Leu and Trp-62-->Gly mutants indicated that the structural effects of Trp-62 replacements were localized in the loop region around position 62 and the part of the beta-sheet containing the hydrogen bonding network important for enzymatic activity. Thus, we conclude that Trp-62 not only interacts with oligosaccharide through van der Waals contact, but also maintains the local structural conformation to produce the lysozyme-oligosaccharide interaction.

cDNA cloning and sequence of CYP2C29 encoding P-450 MUT-2, a microsomal aldehyde oxygenase

A cDNA clone encoding a cytochrome P-450 (P-450) isozyme was isolated from a mouse liver cDNA library. This P-450, designated CYP2C29, the first member of the mouse CYP2C subfamily to be reported, contained the complete coding region of 490 amino acid residues. The deduced amino acid sequence of CYP2C29 exhibited 83% identity with that of the rat CYP2C7 and had an N-terminal sequence identical to that of P-450 MUT-2, a microsomal aldehyde oxygenase. Two peptides, derived from BrCN cleavage of P-450 MUT-2, were also identical to the cDNA deduced protein of CYP2C29. These results indicate that CYP2C29 cDNA encodes P-450 MUT-2.